Nipple Discharge Or Inversion
Nipple discharge or inversion refers to the spontaneous release of fluid from the nipple or retraction of the nipple inward, which may indicate benign conditions such as duct ectasia or intraductal papilloma, or may signal underlying malignancy such as breast carcinoma.
Nipple discharge refers to any fluid that comes out of the nipple of a non-pregnant, non-lactating breast. It is one of the most common breast complaints presenting to surgical clinics. Strictly speaking, any fluid exiting via the lactiferous duct orifices counts — but clinically we distinguish physiological discharge (e.g. lactation, galactorrhoea) from pathological discharge, because the latter may harbour malignancy in 5–15% of cases [1][2].
Nipple inversion (also called nipple retraction or depression) is the inward pulling of the nipple below the plane of the areola. It can be congenital (failure of mesenchymal proliferation to evert the nipple papilla during development) or acquired (pulled inward by fibrosis, inflammation, or an underlying malignancy retracting the ducts) [2].
The lecture slides list nipple changes under the mnemonic 5Ds: Deviation, Discolouration, Dermatitis, Depression (retraction/inversion), Discharge [1][3]. These are the classical nipple signs to look for when assessing any breast complaint.
- Nipple discharge accounts for approximately 3–5% of breast-related surgical consultations and is the third most common breast complaint after breast pain and breast lumps.
- Among women presenting with nipple discharge, malignancy is the underlying cause in ~5–15% of pathological discharge cases. The most common associated malignancy is ductal carcinoma in situ (DCIS) [2].
- Intraductal papilloma is the single most common cause of pathological (especially bloody) nipple discharge [2][3].
- Galactorrhoea is common in women of reproductive age; prolactinoma is the most common pituitary tumour causing this.
- Congenital nipple inversion is present in roughly 10–20% of women bilaterally and is benign.
- Acquired nipple inversion is much less common but warrants urgent investigation to exclude malignancy, particularly in unilateral, new-onset cases.
Hong Kong Context
- Breast cancer is the most common cancer in Hong Kong women (Hong Kong Cancer Registry), so any pathological nipple discharge or new nipple inversion must be taken seriously.
- Duct ectasia and periductal mastitis are common in Hong Kong's ageing population and among smokers respectively.
- Current Hong Kong guidance emphasizes breast awareness (knowing usual breast appearance/feel and seeking prompt review for changes) plus risk-based mammography, rather than routine monthly scheduled breast self-examination for all women [5].
3. Risk Factors
| Category | Risk Factor | Why? |
|---|---|---|
| Age | Perimenopausal / postmenopausal | Intraductal papillomas peak perimenopausal; DCIS incidence rises with age |
| Benign breast disease | Intraductal papilloma, fibrocystic changes, duct ectasia | Direct ductal pathology → fluid production or bleeding |
| Hormonal | Hyperprolactinaemia (drugs, prolactinoma, hypothyroidism) | Prolactin stimulates milk production even outside pregnancy |
| Medications | Antipsychotics, antiemetics, antidepressants | Block dopamine → remove tonic inhibition on prolactin → galactorrhoea |
| Malignancy | DCIS, invasive ductal carcinoma, Paget's disease | Tumour cells within ducts cause necrosis, angiogenesis → bloody/serous discharge |
| Category | Risk Factor | Why? |
|---|---|---|
| Congenital | Developmental | Failure of mesenchymal proliferation beneath the nipple |
| Inflammatory | Duct ectasia, periductal mastitis, subareolar abscess, TB mastitis, idiopathic granulomatous mastitis | Fibrosis around subareolar ducts contracts and pulls nipple inward |
| Malignancy | Breast carcinoma (especially central/retroareolar) | Tumour infiltrates and shortens the ducts → retraction |
| Smoking | Periductal mastitis association | Smoking is a major risk factor for periductal mastitis in young women → subsequent fibrosis → retraction [2][4] |
4. Anatomy and Function
Understanding the anatomy is essential because nipple discharge and inversion are disorders of the ductal system and the retroareolar structures.
- Normal boundaries: Superior (2nd rib), Inferior (inframammary fold ~6th–7th rib / upper rectus sheath), Medial (lateral border of sternum), Lateral (mid-axillary line / edge of latissimus dorsi) [3][4].
- Depth: Breast tissue sits on the pre-pectoral fascia overlying pectoralis major [4].
- Axillary tail (of Spence): extension of breast tissue between pectoralis major and latissimus dorsi, blending with axillary fat [4].
The TDLU is the functional and structural unit of the breast:
- Each breast contains 15–20 lobes, each drained by a lactiferous duct.
- Each lobe is composed of lobules (10–100 per lobe), and each lobule contains acini (milk-producing glands).
- The lobules drain into ductules → segmental ducts → lactiferous ducts → lactiferous sinuses (ampullae beneath the areola) → nipple orifices.
- The ducts are lined by a double layer: an inner epithelial (luminal) layer and an outer myoepithelial layer. The myoepithelial cells contract to propel milk toward the nipple.
- Ligaments of Cooper: fibrous septa that suspend the breast tissue from the skin to the deep fascia. In carcinoma, tumour infiltrating these ligaments causes skin tethering and dimpling [4].
- The nipple is a cylindrical protrusion of thickened, pigmented skin containing 15–20 lactiferous duct orifices. It is richly innervated (T4 dermatome) and has smooth muscle fibres that cause erection in response to cold/touch.
- The areola surrounds the nipple and contains:
- Montgomery's tubercles (modified sebaceous glands) — lubricate the nipple during lactation.
- Involuntary (smooth) muscle arranged in concentric rings and radial fibres — when these contract, the nipple becomes erect and shorter, helping with milk ejection.
- Subareolar ducts converge beneath the nipple. Pathology in this region (duct ectasia, periductal mastitis, subareolar abscess, central tumour) directly affects nipple appearance and discharge.
- Discharge arises from pathology within the ducts (papilloma, DCIS, duct ectasia) or from outside stimulation of duct secretion (prolactin-mediated galactorrhoea).
- Inversion occurs when the subareolar structures (ducts, periductal connective tissue) are shortened or fibrosed. Congenitally, the mesenchyme simply never pushed the papilla out. Acquired inversion means something is pulling the nipple inward — think fibrosis (duct ectasia, mastitis) or infiltration (carcinoma).
- A single-duct discharge localises pathology to one duct system (e.g. solitary papilloma, DCIS). Multiple-duct discharge is more often benign or systemic (galactorrhoea, fibrocystic changes, duct ectasia).
- Internal thoracic (mammary) artery ← Subclavian artery [4]
- Lateral thoracic artery ← Axillary artery [4]
- Posterior intercostal arteries
- Intraductal papillomas have muscularis arteries running through their peduncle that supply the neoplasm. However, the lymphatics and veins within the papilloma are compromised, leading to elevated vascular pressure and transudation of fluid into the duct (serous discharge) or frank bleeding (bloody discharge) when fragile vessels rupture [2].
- Axillary lymph nodes drain ~75% of breast lymph (5 groups: anterior, posterior, medial, lateral, apical) [4].
- Internal mammary (parasternal) lymph nodes drain medial breast (~25%) — run with the internal thoracic artery [4].
- Lymphatic obstruction by tumour can cause peau d'orange (oedema of skin between hair follicle pits).
5. Etiology and Pathophysiology
We organise causes of nipple discharge into three broad categories — lactation/galactorrhoea, pathological discharge, and causes of nipple inversion.
5.1 Nipple Discharge — Aetiological Categories
- Normal milk production during pregnancy, postpartum and for up to 6 months to 2 years after cessation of breastfeeding.
- Bloody nipple discharge can occur in ~20% of women during the 2nd or 3rd trimester and during lactation — this is usually benign (caused by rapidly proliferating ductal epithelium and increased vascularity) [2].
"Galactorrhoea" → from Greek: gala = milk, rhoia = flow.
- Typically bilateral, involving multiple ducts, and milky in appearance.
- The underlying mechanism is almost always hyperprolactinaemia — prolactin is the key hormone driving milk synthesis by mammary alveolar epithelial cells.
Why does prolactin go up?
Normally, prolactin secretion from anterior pituitary lactotroph cells is under tonic inhibitory control by dopamine from the hypothalamus (via the tuberoinfundibular pathway). Anything that:
- Produces prolactin autonomously (prolactinoma),
- Blocks dopamine (drugs), or
- Interrupts the dopamine pathway (stalk compression, infiltrative disease) → removes tonic inhibition → prolactin rises → galactorrhoea.
| Cause | Examples | Mechanism |
|---|---|---|
| Hypothalamic-pituitary disease | Prolactinoma (lactotroph adenoma) — most common pituitary tumour | Autonomous prolactin secretion |
| Craniopharyngioma, metastatic cancer | Stalk compression → dopamine cannot reach lactotrophs | |
| Infiltrative disease (sarcoidosis) | Same stalk-effect mechanism | |
| Head trauma / surgery | Disrupts hypothalamic-pituitary axis | |
| Drug-induced | Antipsychotics (haloperidol, risperidone) — most common drug cause | D2 receptor blockade on lactotrophs → removes dopamine inhibition |
| Antiemetics (metoclopramide, domperidone) | D2 receptor blockade (same mechanism) | |
| Antidepressants (amitriptyline, clomipramine) | Serotonin stimulates prolactin release; some also have mild D2-blocking activity | |
| Endocrine | Hypothyroidism | ↑ TRH → TRH stimulates prolactin release; also ↓ metabolic clearance of prolactin |
| Chronic kidney disease | ↓ Renal clearance of prolactin | |
| Miscellaneous | Stress, chest wall stimulation | Afferent neural arc stimulates prolactin release |
Exam Tip — Hypothyroidism and Galactorrhoea
A common exam question: Why does hypothyroidism cause galactorrhoea? Two mechanisms: (1) ↑ TRH (thyrotropin-releasing hormone) cross-stimulates prolactin release from lactotrophs because TRH receptors are present on lactotrophs; (2) ↓ metabolic clearance of prolactin in hypothyroid states. Always check TFTs in a patient with galactorrhoea!
This is the category that surgeons worry about. The hallmarks of pathological discharge are:
- Spontaneous (comes out without squeezing)
- Persistent
- Unilateral
- Single-duct
- Serous (clear/yellow), sanguineous (bloody), or serosanguineous (blood-tinged)
Key slide point: History must determine — unilateral or bilateral, blood-stained/milky/serous, spontaneous or on manual expression; on examination — single duct or multiple duct, nature/colour of discharge, any palpable breast mass or axillary lymph node [1].
| Cause | Discharge Colour | Pathophysiology |
|---|---|---|
| Intraductal papilloma (most common cause of pathological discharge) | Bloody, serous, or serosanguineous | Benign papillary tumour within a duct. Muscularis arteries run through the peduncle supplying the papilloma, but veins and lymphatics are compromised → elevated intravascular pressure → transudation (serous) or rupture of fragile vessels (bloody) [2] |
| Duct ectasia | Creamy, cheesy, multi-coloured (green/blue/black, occasionally blood-tinged) | Subareolar ducts dilate with age → stagnant secretions become inspissated → fibrosis and inflammation. The cheesy material is essentially old, degenerated duct contents [2][4] |
| Fibrocystic breast changes (FBC) | Serous or serosanguineous | Exaggerated cyclical hormonal response → epithelial hyperplasia, cyst formation, and active intraductal component → ductal fluid accumulation. Active intraductal hyperplasia can bleed [2] |
| DCIS | Bloody or serous | Malignant cells proliferate within ducts → necrosis (especially comedo-type DCIS with central necrosis) → debris and blood leak into the duct lumen [2][3] |
| Invasive ductal carcinoma (IDC) | Bloody | Tumour invades and erodes duct walls and their blood vessels → frank bleeding into duct system |
| Periductal mastitis / breast abscess | Purulent | Infection of periductal tissue → pus formation → discharge through duct orifice [2] |
| Paget's disease of the nipple | Bloody, serous | Malignant intraepithelial adenocarcinoma cells (Paget cells) infiltrate and proliferate in the epidermis of the nipple, causing thickening of the nipple and areolar skin [1]. Associated with underlying DCIS or invasive cancer (~80% of cases). Presents with eczematous changes involving the nipple [1][2] |
High Yield — Bloody Nipple Discharge
Do NOT assume bloody discharge is benign. The differential includes intraductal papilloma (most common), DCIS, invasive carcinoma, and fibrocystic changes with active intraductal component. All cases of spontaneous bloody single-duct discharge need triple assessment (clinical + radiological + pathological) to exclude malignancy.
5.2 Nipple Inversion — Aetiological Categories
- Usually bilateral and benign.
- Results from failure of the underlying mesenchymal tissue to proliferate and project the nipple papilla outwards during development [2].
- Very common (~10–20% of women). The nipple can often be manually everted.
- No association with malignancy.
Acquired = new-onset in someone who previously had a normal, everted nipple. This is the clinically worrying scenario.
| Cause | Mechanism of Inversion |
|---|---|
| Underlying malignancy (breast carcinoma) | Tumour grows along/around the lactiferous ducts → fibrotic reaction and direct shortening/retraction of ducts → pulls nipple inward. A central/retroareolar tumour is the classic culprit. The retraction is usually unilateral, progressive, and irreversible (you cannot manually evert the nipple) |
| Duct ectasia | Dilated subareolar ducts undergo periductal fibrosis → the fibrotic tissue contracts → retracts nipple [2][4] |
| Periductal mastitis | Chronic periductal inflammation → fibrosis → shortening of ducts → retraction [2] |
| Subareolar abscess and periareolar fistula | Abscess formation and healing with scar tissue → duct damage → fibrosis and retraction [2] |
| Tuberculosis mastitis | Granulomatous inflammation → extensive fibrosis → retraction (rare but seen in TB-endemic areas) [2] |
| Idiopathic granulomatous mastitis (IGM) | Non-caseating granulomatous inflammation of unknown aetiology → fibrosis → retraction [2] |
Congenital vs Acquired Nipple Inversion — How to Tell
- Congenital: bilateral, longstanding (since puberty), the nipple can be manually everted ("Grade 1–2"), no associated mass or skin changes. - Acquired: new-onset, usually unilateral, often progressive, may be associated with mass/discharge/skin changes. Always exclude malignancy with triple assessment.
6. Classification
| Type | Appearance | Significance |
|---|---|---|
| Milky | White, opaque | Lactation or galactorrhoea — almost always benign/systemic |
| Serous | Clear or yellow, straw-coloured | Intraductal papilloma (classical), fibrocystic changes, rarely DCIS |
| Bloody / Sanguineous | Red, frank blood | Intraductal papilloma (bleeding), DCIS, IDC, fibrocystic changes with active intraductal hyperplasia |
| Serosanguineous | Blood-tinged yellow/pink | Same differential as bloody |
| Purulent | Opaque, yellow-green, foul | Mastitis, periductal mastitis, breast abscess |
| Multi-coloured / cheesy | Green, blue, black, creamy | Duct ectasia (classical) |
Physiological/Benign:
- Bilateral, multi-duct, non-spontaneous (only on expression), milky
- E.g. Lactation, galactorrhoea, fibrocystic changes
Pathological/Suspicious:
- Unilateral, single-duct, spontaneous, persistent, serous or bloody
- E.g. Intraductal papilloma, DCIS, IDC
This distinction matters because pathological discharge mandates triple assessment and often surgical intervention, whereas physiological discharge can often be managed conservatively.
| Grade | Description | Implication |
|---|---|---|
| Grade 1 | Nipple easily everted manually and maintains projection | Minimal fibrosis; often congenital; breastfeeding usually possible |
| Grade 2 | Nipple can be everted but retracts immediately | Moderate fibrosis; some difficulty breastfeeding |
| Grade 3 | Nipple cannot be everted at all | Severe fibrosis or underlying mass pulling it in; breastfeeding not possible; must exclude malignancy |
7. Clinical Features
| Symptom | Pathophysiological Basis |
|---|---|
| Nipple discharge — spontaneous staining of bra/clothing | Fluid produced by intraductal pathology (papilloma, DCIS) or secretory stimulation (prolactin) exceeds the duct's capacity → leaks out spontaneously |
| Bloody discharge | Fragile vessels in a papilloma rupture or tumour necrosis (DCIS comedo-type) erodes vessel walls → blood mixes with ductal fluid |
| Milky discharge unrelated to breastfeeding | Hyperprolactinaemia stimulates alveolar epithelial cells to produce casein, lactose, and lipid → milky secretion |
| Creamy/cheesy/multi-coloured discharge | Inspissated (thickened, dried) secretions in dilated ectatic ducts break down and change colour (lipofuscin pigment → green/blue/black) |
| Purulent discharge | Bacterial infection in periductal tissue or abscess cavity → pus drains via the duct |
| Nipple sinking inward (inversion) | Fibrosis shortening ducts (duct ectasia, periductal mastitis) or tumour infiltrating and retracting ducts |
| Breast lump (associated) | Underlying papilloma (small, subareolar), carcinoma (hard, irregular), or abscess (tender, fluctuant) |
| Breast pain | Engorgement (lactational mastitis), cyst enlargement (fibrocystic changes), abscess formation (infection), or inflammatory carcinoma |
| Eczema / itching of nipple | Paget's disease — malignant Paget cells in the epidermis trigger an inflammatory/eczematous reaction [1] |
| Constitutional symptoms (weight loss, fatigue, bone pain) | Suggest advanced malignancy with metastatic disease |
Key History Points to Elicit
As taught on the lecture slides [1]:
Symptom history: Unilateral or bilateral? Blood-stained, milky, or serous? Spontaneous or on manual expression?
Sign history: Single duct or multiple duct? Colour of discharge? Any palpable breast mass? Axillary lymph nodes?
Additional history:
- Recent pregnancy / breastfeeding? (→ lactation vs pathological)
- Medications? (→ drug-induced galactorrhoea)
- Menstrual history? (→ cyclical changes suggest fibrocystic disease)
- Duration and progression? (→ new and progressive = worrying)
- Risk factors for breast cancer? (→ family history, BRCA status, prior breast disease, oestrogen exposure)
7.2 Signs (What You Find on Examination)
Physical examination follows the standard breast examination approach [3][4]:
Position: 45° upright or sitting, exposure from clavicle to upper abdomen, both breasts and axillae exposed.
| Sign | What It Looks Like | Pathophysiological Basis |
|---|---|---|
| Nipple discharge (express or spontaneous) | Fluid from nipple orifice — note colour, duct involved | See above; single duct → focal pathology; multiple ducts → diffuse/systemic |
| Nipple inversion / retraction (Depression) | Nipple pulled below the areolar plane | Fibrosis (duct ectasia, mastitis) or tumour infiltration shortening the ducts |
| Nipple deviation / displacement | Nipple points in abnormal direction | Asymmetric fibrosis or tumour mass displacing the nipple |
| Nipple discolouration | Darkening or erythema of nipple/areola | Increased vascularity (inflammation) or Paget's disease |
| Nipple eczema / dermatitis | Scaly, crusted, erythematous, ulcerated nipple | Paget's disease — malignant Paget cells in the epidermis cause thickening, scaling, and ulceration of the nipple-areolar skin [1] |
| Skin dimpling / tethering | Skin puckers when arms raised | Tumour infiltrating Cooper's ligaments → shortens them → pulls skin inward [4] |
| Peau d'orange | Skin resembles orange peel (oedema with pitting at hair follicle sites) | Tumour blocks dermal lymphatics → lymphoedema; the hair follicles and sweat gland openings are tethered and don't swell → the surrounding oedematous skin protrudes around them [2][3] |
| Erythema / swelling | Red, warm, swollen breast | Infection (mastitis/abscess) or inflammatory breast cancer (tumour in dermal lymphatics) |
| Skin ulceration | Breakdown of overlying skin | Locally advanced tumour eroding through skin |
| Sign | Finding | Significance |
|---|---|---|
| Subareolar mass | Firm, retroareolar lump | Intraductal papilloma, duct ectasia, periductal mastitis/abscess, or central carcinoma |
| Breast mass | Hard, irregular, fixed, non-tender | Carcinoma — 50% occur in the upper outer quadrant [2]; fixation to skin or pectoralis major is almost diagnostic |
| Trigger point for discharge | Pressing on a specific area produces discharge from a single duct | Helps localise the pathological duct (valuable for planning microdochectomy) |
| Axillary lymphadenopathy | Hard, matted, fixed nodes | Metastatic carcinoma; soft, tender nodes suggest reactive/infective |
| Tenderness | Painful on palpation | Inflammatory pathology (mastitis, abscess, fibrocystic changes) or advanced malignancy with skin involvement |
Clinical Pearl — How to Express Nipple Discharge
To determine the involved duct, gently compress the breast in a radial fashion (like "clock positions") moving toward the nipple. If pressure at a specific clock position produces discharge from a single duct orifice, this localises the pathological duct to that segment. This is the basis of microdochectomy planning.
- Hands on hips / press inward → contracts pectoralis major → accentuates skin dimpling/tethering and fixation to muscle.
- Arms overhead → stretches skin → reveals subtle skin changes and asymmetry.
- Lean forward → breasts hang freely → any mass fixed to the chest wall will not swing with the breast.
8. Specific Conditions Causing Nipple Discharge or Inversion — Pathophysiology Deep Dive
- "Papilloma" → from Latin papilla (nipple-like projection) + Greek -oma (tumour). Literally a nipple-like tumour within a duct.
- A benign papillary neoplasm of the ductal epithelium with a fibrovascular core (stalk/peduncle).
- Can be solitary (central, subareolar — classic presentation with discharge) or multiple (peripheral — diffuse papillomatosis defined as ≥ 5 papillomas within a localised segment) [2].
- Multiple papillomas carry an increased risk of breast cancer [4].
- Pathophysiology of discharge: The peduncle contains muscularis arteries that adequately supply the papilloma, but the lymphatics and veins are compromised → ↑ vascular pressure → transudate forms in the duct (serous discharge). If the fragile vessels rupture → bloody discharge [2].
- Diagnosed by core needle biopsy [2].
- Managed by microdochectomy (surgical excision of the single affected lactiferous duct and its associated lobules) — this is the standard approach [2][4].
- "Ectasia" → from Greek ektasis = dilation/stretching.
- Characterised by abnormal dilatation of subareolar ducts with fibrosis and inflammation [4].
- An age-related phenomenon primarily affecting older women [2].
- NOT associated with increased risk of breast cancer [2].
- NOT associated with significant periareolar inflammation or infection (distinguishing it from periductal mastitis) [2].
- Pathophysiology: Subareolar ducts dilate → secretions become stagnant and inspissated → cheesy material accumulates → periductal fibrosis develops → nipple retraction. If ducts become blocked → predisposes to secondary periductal mastitis or abscess.
- Clinical features: Palpable subareolar mass, nipple inversion, creamy cheesy nipple discharge that is multi-coloured (green/blue/black, occasionally blood-stained) [2].
- Management: Conservative (often resolves spontaneously, sometimes with residual subareolar nodule). Microdochectomy if persistent [2].
- Inflammatory condition of the subareolar ducts with unknown aetiology.
- Affects young women — majority are smokers [2].
- Pathophysiology: Smoking is thought to damage the subareolar duct epithelium either directly (toxic metabolites in breast secretions) or via ischaemia → squamous metaplasia of duct lining → keratinous debris plugs the duct → secondary bacterial infection → periductal inflammation → abscess formation → duct rupture → periareolar fistula.
- Organisms: Staphylococci, Streptococci, Enterococci, Bacteroides, Proteus (mixed aerobic-anaerobic flora) [2].
- Clinical features: Painful, tender retroareolar mass; purulent nipple discharge; subareolar abscess; periareolar fistula (communication between a subareolar duct and the skin).
- Management: Antibiotics (Augmentin or Dicloxacillin + Metronidazole); abscess drainage (USG-guided FNA or I&D); fistulectomy ± total duct excision [2].
- The most frequent benign disorder of the breast [2].
- Not a single disease but a spectrum of histopathological changes: stromal fibrosis, macro/microcysts, apocrine metaplasia, hyperplasia, adenosis [2].
- Affects premenopausal women; driven by oestrogen predominance over progesterone.
- Discharge (serous or serosanguineous) occurs when there is an active intraductal component — intraductal hyperplasia or cystic fluid leakage.
- Usually associated with cyclical mastalgia and nodularity (upper outer quadrant).
- Eczematous changes involving the nipple, associated with malignancy within the same breast [1].
- Malignant epithelial (Paget) cells infiltrate and proliferate in the epidermis, causing thickening of the nipple and areolar skin [1].
- Almost always (~80%) associated with underlying breast cancer, which is HER2-positive [2].
- Presents with pain, burning, pruritus, palpable breast mass, bloody nipple discharge, or nipple inversion [2].
- Pathogenesis: Two theories:
- Epidermotropic theory (favoured): Malignant ductal cells migrate from an underlying DCIS or invasive carcinoma along the lactiferous ducts to colonise the nipple epidermis.
- In-situ transformation theory: Epidermal keratinocytes undergo malignant transformation independently.
- Diagnosis: Full-thickness wedge biopsy of the nipple and underlying breast tissue — pathological hallmark is malignant intraepithelial adenocarcinoma cells (Paget cells) within the nipple epidermis [2].
- Mammography is mandatory to look for associated mass and exclude synchronous cancers or widespread calcification [2].
- Treatment: Excision of the underlying cancer AND the nipple-areolar complex — both mastectomy or BCT followed by whole-breast irradiation are acceptable [2].
Exam Pearl — Paget's Disease
Any unilateral nipple eczema in a middle-aged/older woman is Paget's disease until proven otherwise. Do NOT treat with steroid cream without biopsy. Paget's is almost always associated with underlying breast cancer (HER2-positive in majority). Mammography is mandatory.
| Cause | Age Group | Discharge Character | Duct(s) | Side | Key Associations |
|---|---|---|---|---|---|
| Lactation | Reproductive | Milky | Multiple | Bilateral | Pregnancy, postpartum |
| Galactorrhoea | Any | Milky | Multiple | Bilateral | Drugs, prolactinoma, hypothyroidism, CKD |
| Intraductal papilloma | Perimenopausal | Bloody / serous | Single | Unilateral | Most common cause of pathological discharge |
| Duct ectasia | Older (>50) | Cheesy, multi-coloured | Multiple | Unilateral/bilateral | Nipple inversion, subareolar mass, NOT ↑ CA risk |
| Fibrocystic changes | Premenopausal | Serous / serosanguineous | Multiple | Bilateral | Cyclical mastalgia, nodularity |
| DCIS | Older | Bloody / serous | Single | Unilateral | Microcalcifications on mammogram |
| Invasive carcinoma | Older | Bloody | Single | Unilateral | Hard mass, axillary LN |
| Paget's disease | Older | Bloody / serous | N/A (epidermis) | Unilateral | Nipple eczema, HER2+ cancer |
| Periductal mastitis | Young smokers | Purulent | Single/multiple | Unilateral | Subareolar abscess, fistula |
| Mastitis / abscess | Lactating | Purulent | Multiple | Unilateral | S. aureus, breastfeeding |
| Cause | Bilateral/Unilateral | Mechanism | Key Feature |
|---|---|---|---|
| Congenital | Bilateral | Failure of mesenchymal proliferation | Present since puberty, manually evertible |
| Breast carcinoma | Unilateral | Tumour infiltration → duct shortening | Hard mass, progressive, non-evertible |
| Duct ectasia | Usually unilateral | Periductal fibrosis → contraction | Cheesy discharge, older women |
| Periductal mastitis | Unilateral | Inflammation → fibrosis | Young smoker, tender mass |
| Subareolar abscess / fistula | Unilateral | Scar tissue from abscess healing | Recurrent infections |
| TB mastitis | Unilateral | Granulomatous inflammation → fibrosis | Caseating granulomas on biopsy |
| Idiopathic granulomatous mastitis | Unilateral | Non-caseating granulomas → fibrosis | Diagnosis of exclusion |
High Yield Summary
-
Nipple discharge is classified as physiological (lactation, galactorrhoea) or pathological (serous, bloody, purulent). Pathological discharge is spontaneous, unilateral, single-duct, and serous/bloody.
-
Intraductal papilloma is the most common cause of pathological (especially bloody) nipple discharge. The bloody/serous discharge results from compromised venous/lymphatic drainage in the papilloma's peduncle.
-
Malignancy (DCIS > IDC) accounts for 5–15% of pathological nipple discharge. DCIS is the most common malignancy associated.
-
Galactorrhoea = milky, bilateral, multi-duct. Think hyperprolactinaemia — prolactinoma, drugs (antipsychotics/antiemetics), hypothyroidism, CKD.
-
Duct ectasia = older women, cheesy multi-coloured discharge, nipple inversion, NOT increased cancer risk.
-
Paget's disease = unilateral nipple eczema + underlying breast cancer (HER2+ in ~80%). Paget cells in nipple epidermis. Biopsy is mandatory. Do NOT treat as dermatitis without histology.
-
Nipple inversion: Congenital (bilateral, benign, manually evertible) vs Acquired (unilateral, progressive, must exclude malignancy). Acquired causes: carcinoma, duct ectasia, periductal mastitis, abscess/fistula, TB, IGM.
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5Ds of nipple changes: Deviation, Discolouration, Dermatitis, Depression (retraction/inversion), Discharge.
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History essentials for nipple discharge: unilateral/bilateral, colour, spontaneous/expressed, single/multiple duct, associated mass/lymphadenopathy, pregnancy/lactation, medications, cancer risk factors.
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All pathological nipple discharge requires triple assessment (clinical + radiological + pathological).
Active Recall - Nipple Discharge and Inversion
[1] Lecture slides: GC 181. Breast mass breast cancer; benign breast diseases; mammography; breast cancer screening.pdf (p16, p34) [2] Senior notes: felixlai.md (Chapters on Nipple discharge and inversion pp.269–271, Fibrocystic breast changes pp.272–275, Neoplasms pp.275–276, Infective and inflammatory breast diseases pp.279–282, Breast cancer risk factors and clinical features pp.284–289) [3] Senior notes: maxim.md (Sections 8.2–8.6: Common breast complaints, Assessment of breast mass, Benign breast disease, Benign breast tumours pp.178–189) [4] Senior notes: maxim.md (Section 8.1: Anatomy p.176; Section 8.5: Benign breast disease – inflammatory and non-inflammatory conditions) [5] Hong Kong Cancer Information Website (cancer.gov.hk). Breast cancer page with CEWG screening guidance: https://www.cancer.gov.hk/en/hong_kong_cancer/common_cancers_in_hong_kong/breast_cancer.html
Differential Diagnosis of Nipple Discharge and Nipple Inversion
The differential diagnosis (DDx) of nipple discharge and nipple inversion is best approached systematically by thinking about where the pathology sits — is it systemic/hormonal (galactorrhoea), within the duct lumen (papilloma, DCIS), in the periductal tissue (duct ectasia, mastitis), or in the nipple epidermis itself (Paget's)? For nipple inversion, think: is the nipple being pulled in by fibrosis or tumour, or was it never pushed out (congenital)?
The clinical approach always starts by asking the key discriminating questions from the lecture slides:
Symptom: Unilateral or bilateral? Blood-stained / milky / serous? Spontaneous or on manual expression? Sign: Single duct or multiple duct? Nature of discharge (colour)? Any palpable breast mass / axillary lymph node? [1]
These questions immediately stratify risk and narrow the differential.
1. Framework for Differential Diagnosis of Nipple Discharge
The single most important branching point is the character and laterality of the discharge. Here is a structured approach:
- Milky → Think galactorrhoea (bilateral, multiple ducts) or physiological lactation.
- Why milky? Prolactin drives alveolar epithelial cells to synthesise casein, lactose, and lipids — the same composition as breast milk. The discharge looks milky because it is milk, just produced at the wrong time.
- Non-milky (serous, bloody, serosanguineous, purulent, multi-coloured/cheesy) → Think pathological discharge from an intraductal or periductal lesion.
| Discharge Colour | Most Likely Diagnosis | Why That Colour? |
|---|---|---|
| Milky (white, opaque) | Lactation, galactorrhoea | Actual milk — casein and fat globules scatter light → white |
| Serous (clear / straw-yellow) | Intraductal papilloma (classical) [2] | Transudate forms because venous/lymphatic drainage in the papilloma peduncle is compromised → elevated vascular pressure → plasma-like fluid leaks into the duct |
| Bloody / sanguineous | Intraductal papilloma (bleeding), DCIS, IDC, fibrocystic changes with active intraductal hyperplasia [2] | Fragile neovessels in papilloma rupture; or tumour necrosis (comedo DCIS) erodes vessel walls; or hyperplastic epithelium is hypervascular |
| Serosanguineous (blood-tinged) | Same differential as bloody | Mix of transudate + small amount of blood |
| Creamy / cheesy / multi-coloured (green, blue, black) | Duct ectasia [2][4] | Stagnant inspissated secretions in dilated ducts undergo lipid peroxidation and accumulate lipofuscin pigment → greenish-black colour. The cheesy consistency is from degenerated epithelial cells and lipid debris |
| Purulent (yellow-green, foul) | Periductal mastitis, lactational mastitis, breast abscess [2][4] | Bacterial infection → neutrophilic infiltrate → pus (dead neutrophils + bacteria + liquefied tissue) drains via the duct |
| Yellow / green (non-purulent) | Fibrocystic changes, duct ectasia, hyperprolactinaemia, infection [3] | Cystic fluid or altered duct secretions |
2. Differential Diagnosis — Organised by Presentation
| Diagnosis | Typical Age | Character | Duct(s) | Side | Key Distinguishing Features | Pathophysiology |
|---|---|---|---|---|---|---|
| Physiological lactation | Reproductive | Milky | Multiple | Bilateral | Pregnant, postpartum, or within 2 years of cessation of breastfeeding | Prolactin + oxytocin drive milk synthesis and ejection |
| Galactorrhoea | Any | Milky | Multiple | Bilateral | Not pregnant/lactating; drug history (antipsychotics, antiemetics); hypothyroidism; CKD; prolactinoma | Hyperprolactinaemia — loss of tonic dopamine inhibition → ↑ prolactin → milk synthesis [2] |
| Intraductal papilloma | Perimenopausal | Bloody / serous / serosanguineous | Single | Unilateral | Most common cause of pathological nipple discharge [2][3]; small subareolar lump; discharge often triggered by pressure at a specific clock position | Benign papillary tumour with fibrovascular core; compromised venous/lymphatic drainage → transudate (serous) or vessel rupture (bloody) [2] |
| Duct ectasia | Older ( > 50) | Creamy, cheesy, multi-coloured (green/blue/black) | Multiple | Uni- or bilateral | Subareolar mass, nipple inversion; NOT associated with increased risk of CA breast [2][5] | Age-related dilatation of subareolar ducts → stagnant secretions → inspissation → periductal fibrosis |
| Fibrocystic changes (FBC) | Premenopausal | Serous / serosanguineous | Multiple | Often bilateral | Most frequent benign disorder of the breast [2]; cyclical mastalgia; nodularity worsening before menses | Oestrogen predominance → epithelial hyperplasia, cyst formation, intraductal component → fluid/blood [2] |
| Breast cyst | Premenopausal | Serous (if leaking) | Variable | Uni- or bilateral | Smooth, firm, mobile, fluctuant lump; USG shows fluid-filled cavity | Fluid accumulates in TDLU due to obstruction of efferent ductule [2] |
| DCIS | Older | Bloody / serous | Single | Unilateral | Microcalcifications on mammography; malignancy is the underlying cause in 5–15% of pathological discharge [2]; most common malignancy associated with discharge | Malignant cells proliferate within ducts → comedo necrosis → debris and blood leak into lumen [2][6] |
| Invasive ductal carcinoma (IDC) | Older | Bloody | Single | Unilateral | Hard, irregular, fixed mass; peau d'orange; axillary lymphadenopathy; 50% in upper outer quadrant [2] | Tumour invades and erodes duct walls and vessels → frank bleeding |
| Paget's disease of the nipple | 50–60 years | Bloody / serous | N/A (epidermis) | Unilateral | Eczematous changes involving the nipple [1][7]; 97% has underlying breast carcinoma, about half present with a breast mass [7]; Paget cells arise from mammary ducts to the nipple epidermis [7]; erythema and eczematous lesion → erosion and ulceration [7] | Malignant ductal cells migrate via lactiferous ducts to colonise nipple epidermis (epidermotropic theory) |
| Lactational mastitis / abscess | Lactating | Purulent | Multiple | Unilateral | First 3 months of breastfeeding; S. aureus most common [2][4]; painful, red, swollen breast; abscess = fluctuant mass + fever | Stagnant milk + bacteria → infection → pus |
| Periductal mastitis / non-puerperal abscess | Young | Purulent | Single/multiple | Unilateral | Majority are smokers [2]; subareolar abscess; periareolar fistula | Smoking → squamous metaplasia → keratinous debris → duct obstruction → secondary infection → abscess → fistula [2] |
| Idiopathic granulomatous mastitis | Young parous | Variable (may have discharge) | Variable | Unilateral | Mimics CA breast [2]; diagnosis of exclusion; self-limiting; NO increased risk of CA breast [2] | Non-caseating granulomatous inflammation centred on lobules → fibrosis |
| Fat necrosis | Any | Nipple retraction (not discharge per se) | N/A | Unilateral | History of trauma or breast surgery; mimics CA clinically and radiologically [4] | Ischaemic necrosis of fat lobules → fibrosis → skin dimpling/nipple retraction |
Key Discriminators in Nipple Discharge DDx
When you see a question about nipple discharge, mentally run through these 4 discriminators in order:
- Milky vs non-milky → separates galactorrhoea/lactation from everything else
- Unilateral vs bilateral → unilateral is more worrying
- Single duct vs multiple duct → single duct = focal pathology (papilloma, DCIS, IDC)
- Spontaneous vs expressed → spontaneous = more likely pathological
If the answer to all four is "non-milky, unilateral, single duct, spontaneous" → this is pathological discharge and you must exclude malignancy.
| Diagnosis | Bilateral/Unilateral | Evertible? | Key Associated Features | Mechanism of Inversion |
|---|---|---|---|---|
| Congenital | Bilateral | Yes (Grade 1–2) | Present since puberty; no mass, no discharge, no skin changes | Failure of mesenchymal proliferation to project the nipple papilla outwards [2] |
| Breast carcinoma | Unilateral | No (Grade 3) | Hard, irregular, fixed mass; peau d'orange; axillary LN; skin dimpling | Tumour infiltrates along ducts → desmoplastic fibrosis → shortens and retracts ducts → pulls nipple inward |
| Duct ectasia | Usually unilateral | Partially | Cheesy multi-coloured discharge; subareolar mass; older women | Periductal fibrosis from chronic duct dilatation → contraction → retraction [2][5] |
| Periductal mastitis | Unilateral | Partially | Young smoker; tender retroareolar mass; purulent discharge; fistula | Chronic periductal inflammation → fibrosis → duct shortening → retraction [2] |
| Subareolar abscess / periareolar fistula | Unilateral | No | Recurrent infections; draining sinus at areolar margin | Abscess cavity heals with scar tissue → duct damage → contracture → retraction [2] |
| Fat necrosis | Unilateral | No | Trauma / surgery history; painless lump with skin dimpling; mimics CA [4] | Ischaemic fat necrosis → fibrosis → contracture of surrounding tissue → retraction |
| TB mastitis | Unilateral | No | Chronic sinus; caseating granulomas on biopsy; endemic area | Granulomatous inflammation → extensive fibrosis → retraction [2] |
| Idiopathic granulomatous mastitis | Unilateral | No | Young parous woman; diagnosis of exclusion; mimics CA [2] | Non-caseating granulomas → fibrosis → retraction |
3. Special Differentials Worth Discussing in Detail
This comes up repeatedly because it is a classic exam trap.
- Paget cells arise from mammary ducts to the nipple epidermis [7]
- Erythema and eczematous lesion of the nipple → erosion and ulceration [7]
- 50–60 years old [7]
- 97% has underlying breast carcinoma, about half present with a breast mass [7]
- Diagnosis: incisional biopsy [7]
- Treat underlying CA breast [7]
- The underlying breast cancer is almost always HER2-positive [2]
Why is it commonly misdiagnosed? Because it looks like nipple eczema/dermatitis, and patients (and sometimes doctors) apply topical steroids for months before realising it's not responding. The key differentiator: unilateral nipple eczema in a middle-aged woman that does not respond to topical steroids = Paget's until proven otherwise.
| Feature | Eczema / Dermatitis | Paget's Disease |
|---|---|---|
| Laterality | Often bilateral | Unilateral |
| Starts at | Areola → spreads to nipple | Nipple → spreads to areola |
| Response to steroids | Improves | Does not improve |
| Underlying mass | No | Yes (~50%) |
| Biopsy | Spongiotic dermatitis | Paget cells (large, pale, intraepidermal adenocarcinoma cells) |
Exam Trap — Paget's vs Eczema
If the question describes unilateral nipple eczema that starts at the nipple and does not respond to steroids → answer is Paget's disease. Always biopsy. Eczema is bilateral and starts at the areola. Paget's is unilateral and starts at the nipple.
This is sometimes confused with mastitis because both present with a painful, red, swollen breast. But inflammatory breast cancer (IBC) is caused by invasion of local (dermal) lymphatic ducts by tumour cells, NOT by infection [3].
| Feature | Lactational Mastitis | Inflammatory Breast Cancer |
|---|---|---|
| Age | Young, lactating | Older, non-lactating |
| Onset | Acute | Subacute (weeks) |
| Response to antibiotics | Improves in 48–72 h | Does NOT improve |
| Fever | Yes | May or may not |
| Skin | Focal erythema | Cutaneous oedema involving ≥ 1/3 of breast (peau d'orange) [3] |
| Mass | Fluctuant (abscess) | Diffuse induration |
| Biopsy | Inflammatory cells | Carcinoma cells in dermal lymphatics |
When nipple discharge or inversion is accompanied by a palpable lump, use the classic age-based framework [3]:
| Young ( < 35) | Old ( > 35) | |
|---|---|---|
| Soft | Fibrocystic changes | Fibrocystic changes |
| Firm | Fibroadenoma | Carcinoma |
| Fat necrosis | Fat necrosis | |
| Lipoma | Lipoma | |
| Breast cyst (tense, fluctuant) | Phyllodes tumour (freely mobile) |
The following Mermaid diagram shows the stepwise approach to differentiating nipple discharge:
And for nipple inversion:
This is relevant because some conditions in the DDx are not just benign — they confer a higher risk of future invasive breast cancer. The American College of Pathologists Consensus Statement stratifies this [3]:
| Risk Category | Conditions | Relative Risk |
|---|---|---|
| No increased risk | Adenosis, apocrine metaplasia, cysts (macro/micro), duct ectasia, fibroadenoma, fibrosis, mild hyperplasia, mastitis, periductal mastitis, squamous metaplasia | 1.0× |
| Slightly increased risk | Moderate/florid hyperplasia (solid or papillary), papilloma with fibrovascular core | 1.5–2× |
| Moderately increased risk | Atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH) | 5× |
| Insufficient data | Solitary papilloma of lactiferous sinus, radial scar lesion | Unknown |
Why does this matter for nipple discharge DDx? If you diagnose an intraductal papilloma on biopsy, the patient has a slightly increased risk of future breast cancer. If ADH is found, the risk jumps to 5× — and this changes the surveillance strategy (yearly mammography, twice-yearly breast examination, consideration of chemoprevention with tamoxifen) [2][3].
Multiple papillomas carry an increased risk of CA breast [5]. This is distinct from a solitary central papilloma, which has a lower risk.
6. DDx Summary — Quick Reference by Presentation
- Intraductal papilloma — classical [2]
- Duct ectasia
- DCIS / IDC
- Duct ectasia — virtually pathognomonic [2]
- Breast carcinoma — must exclude first
- Duct ectasia [2]
- Periductal mastitis [2]
- Subareolar abscess / periareolar fistula [2]
- TB mastitis [2]
- Idiopathic granulomatous mastitis [2]
- Fat necrosis [4]
High Yield Summary — Differential Diagnosis
-
Intraductal papilloma is the most common cause of pathological nipple discharge (especially bloody/serous, single-duct, unilateral).
-
DCIS is the most common malignancy associated with nipple discharge (5–15% of pathological discharge).
-
Duct ectasia = older women, cheesy multi-coloured discharge, nipple inversion, NO increased cancer risk.
-
Paget's disease = unilateral nipple eczema starting at the nipple (not areola), 97% has underlying breast CA, diagnosed by incisional biopsy showing Paget cells. Do NOT treat as dermatitis.
-
Galactorrhoea = milky, bilateral, multi-duct → check prolactin, TFTs, drug history, renal function.
-
Key discriminators: milky vs non-milky → unilateral vs bilateral → single vs multiple duct → spontaneous vs expressed → colour.
-
Acquired unilateral nipple inversion = carcinoma until proven otherwise. Always perform triple assessment.
-
Periductal mastitis = young smoker, purulent discharge, subareolar abscess, periareolar fistula. Distinct from duct ectasia (older, non-inflammatory).
-
Risk stratification: duct ectasia and periductal mastitis carry NO increased cancer risk; papilloma carries slightly increased risk (1.5–2×); ADH/ALH carries 5× risk.
Active Recall - Differential Diagnosis of Nipple Discharge and Inversion
References
[1] Lecture slides: GC 181. Breast mass breast cancer; benign breast diseases; mammography; breast cancer screening.pdf (p16) [2] Senior notes: felixlai.md (Nipple discharge and inversion pp.269–271; Fibrocystic breast changes pp.272–275; Neoplasms pp.275–276; Infective and inflammatory breast diseases pp.279–283; Breast cancer risk factors and clinical features pp.284–289) [3] Senior notes: maxim.md (Sections 8.2–8.3: Common breast complaints, Assessment of breast mass pp.178–179; Section 8.7: Relative risk table from ACP Consensus Statement p.182; Risk factors p.183) [4] Senior notes: maxim.md (Section 8.5: Benign breast disease — inflammatory and non-inflammatory conditions pp.185–186) [5] Senior notes: maxim.md (Section 8.6: Benign breast tumours p.187) [6] Senior notes: maxim.md (Carcinoma in-situ: DCIS vs LCIS table p.184) [7] Lecture slides: GC 201. Skin ulcers skin and subcutaneous lesions; skin cancer.pdf (p47); GC 181. Breast mass breast cancer; benign breast diseases; mammography; breast cancer screening.pdf (p34)
Diagnostic Criteria, Diagnostic Algorithm, and Investigation Modalities
There is no single "diagnostic criterion" for nipple discharge or inversion the way there is for, say, diabetes. Instead, the diagnostic approach is built on the Triple Assessment framework — the same systematic approach used for any breast complaint. The reason is simple: the primary concern with pathological nipple discharge or new nipple inversion is excluding malignancy, and no single modality is sensitive enough on its own.
Triple Assessment = Clinical (history + examination) + Radiological (mammogram ± USG) + Pathological (FNAC or core biopsy) [1][8]
Sensitivity 99.6% and specificity 93% [1][8]
Triple Assessment is positive if any of the above is positive, but negative only when all three are negative [8]
If findings do not all correlate, further investigations or monitoring is necessary [8]
Why three components? Because each component has its own blind spots:
| Component | Sensitivity Alone | Blind Spots |
|---|---|---|
| Clinical (history + examination) | 50–85% [8] | Small non-palpable lesions; deep lesions; early DCIS without mass |
| Radiology (mammogram ± USG) | ~90% [8] | Dense breasts in young women (mammogram); microcalcifications (USG); operator-dependent (USG) |
| Pathology (FNAC or core biopsy) | ~91% [8] | Sampling error (FNAC); FNAC cannot distinguish in-situ from invasive (no architecture) |
By combining all three, the overall sensitivity reaches 99.6% — meaning you miss very little. The logic: if any one component flags concern, you proceed with further workup even if the other two are reassuring.
Before launching into investigations, you need to determine whether the discharge warrants full triple assessment or can be managed conservatively. The criteria that define pathological (i.e. "suspicious") nipple discharge are:
| Feature | Pathological | Physiological/Benign |
|---|---|---|
| Spontaneity | Spontaneous (stains bra/clothing without squeezing) [1] | Only on manual expression |
| Laterality | Unilateral [1] | Bilateral |
| Number of ducts | Single duct [1] | Multiple ducts |
| Colour | Blood-stained / serous (clear or yellow) / serosanguineous [1] | Milky, green, multi-coloured cheesy |
| Persistence | Persistent | Intermittent |
| Associated findings | Palpable breast mass and/or axillary lymph node [1] | None |
If the discharge meets pathological criteria → full triple assessment is mandatory.
If the discharge is milky and bilateral → think galactorrhoea → check prolactin, TFTs, drug history, renal function first.
If the discharge is multi-coloured/cheesy in an older woman with no mass → likely duct ectasia → imaging to confirm, but low concern for malignancy.
When to Worry About Nipple Discharge
The combination that should trigger alarm bells: spontaneous + unilateral + single-duct + bloody or serous. This pattern carries a 5–15% risk of underlying malignancy (most commonly DCIS). Even if mammogram is normal, pathological assessment (core biopsy or surgical duct excision) is required.
There are no formal "diagnostic criteria" for nipple inversion itself — you can see it. The diagnostic question is why it is there:
| Scenario | Action |
|---|---|
| Longstanding bilateral, evertible | Congenital — reassure, no further investigation needed |
| New-onset unilateral, non-evertible | Acquired — must exclude malignancy → full triple assessment |
| New-onset + associated features (mass, skin changes, discharge, LN) | High suspicion for carcinoma → urgent triple assessment |
| New-onset + history of inflammation (smoking, recurrent abscess) | Consider periductal mastitis/duct ectasia, but still image to exclude malignancy |
4. The Triple Assessment — Component by Component
This is the first and most important step. It costs nothing, requires no equipment, and immediately stratifies risk.
History — The lecture slides specify the essential questions [1][8]:
Clinical history for patients with breast symptoms: breast symptoms (lump, pain, nipple discharge), further characterisation (duration, changes, unilateral or bilateral, characteristics) [1]
For nipple discharge specifically:
- Symptom: unilateral/bilateral, characteristics (blood-stained/milky/serous), spontaneous or on manual expression [1]
- Recent pregnancy/breastfeeding?
- Drug history (antipsychotics, antiemetics, antidepressants)?
- Menstrual history (cyclical changes suggest fibrocystic disease)?
- Risk factors for breast cancer (FHx, BRCA, prior breast disease, oestrogen exposure) [3]
For nipple inversion:
- When did it start? Present since puberty (congenital) vs new-onset (acquired)?
- Progressive? Can you evert it?
- Associated mass, discharge, skin changes?
Consent / Chaperone / Curtain → Positioning → Exposure → Inspection → Palpation [1]
- Inspection: symmetry, scar, skin changes, special manoeuvre (raise up patient's arms) [1]
- Palpation: breast mass, axillary lymph nodes, nipple discharge (if applicable) [1]
- Express discharge by compressing breast radially toward nipple — identify the "trigger point" and which duct(s) are involved
- Characterise any mass: site, size, shape, border, surface, consistency, tenderness, mobility (to skin and muscle) [3]
- Axillary lymph nodes: anterior, posterior, medial, lateral, apical groups [3]
4B. Radiological Assessment
"Mammography" → from Latin mamma = breast + Greek graphein = to write/record. It is a low-dose X-ray of the breast.
Mammogram: only for female > 35 years (poor resolution in dense breasts in young females) [3]
Why age > 35? Younger women have dense fibroglandular tissue that appears white on mammography — the same colour as tumours. This "white-on-white" problem makes mammography insensitive in young dense breasts. After age 35, breast tissue gradually involutes and is replaced by radiolucent fat, making masses and calcifications much more conspicuous.
- Craniocaudal (CC) view: X-ray beam goes from top to bottom. Shows medial-to-lateral extent. Used to determine inner vs outer quadrant.
- Mediolateral oblique (MLO) view: X-ray beam at 45° angle. Shows the axillary tail, axillary lymph nodes, and upper outer quadrant in detail [2]. Used to determine upper vs lower half (line perpendicular to pectoralis major).
Mammographic features of malignancy [2][3]:
| Feature | Benign | Malignant |
|---|---|---|
| Mass shape | Round, oval, well-circumscribed | Spiculated (stellate) mass with irregular borders [3] |
| Calcification content | Rim-like, large coarse, smooth round/oval | Pleomorphic microcalcifications [2] |
| Calcification distribution | Vascular, skin calcification | Linear branching microcalcifications, clustered microcalcifications ( > 5/mm²) [2] |
| Architecture | Normal | Architectural distortion (e.g. tent sign) [3] |
| Other | — | Pectoralis major involvement (MLO view only), skin thickening/tethering, nipple involvement [3] |
Mammography for nipple discharge specifically:
- Look for microcalcifications (DCIS)
- Look for a retroareolar mass (papilloma, carcinoma)
- Look for dilated calcified ducts (duct ectasia) [4]
- In Paget's disease: mammography is mandatory to look for associated mass and exclude synchronous cancers or widespread calcification [2]
Limitations of mammography [2]:
- Cannot make a definitive diagnosis — can only depict a mass as abnormal or suspicious
- Dense breast tissue can obscure lesions
- Cannot reliably distinguish benign from malignant without biopsy
USG breast: for all patients [3]
Why USG for everyone? Because it complements mammography perfectly — it works best precisely where mammography is weakest (dense breasts, young women, cystic vs solid differentiation).
- Improved sensitivity and specificity combined with mammogram, especially in young women with dense breast tissue [3]
- Distinguish cysts from solid lesions [3] — this is crucial because a simple cyst needs no further intervention
- Guide FNAC, biopsy, and clipping before neoadjuvant chemotherapy [3]
- Assess axillary lymph nodes [3] — suspicious LN: loss of fatty hilum [3]
- First imaging study in young women ( < 35) or women who are pregnant or lactating [2]
- Identify presence of a prominent vascular supply (colour Doppler)
USG features — benign vs malignant [2]:
| Feature | Benign | Malignant |
|---|---|---|
| Shape | Wider-than-taller (ellipsoid) | Taller-than-wide (fir-tree shape) [2] |
| Margin | Smooth margins, macrolobulation | Spiculated or angular margins, microlobulation [2] |
| Echogenicity | Hyperechoic, thin echogenic capsule | Hypoechoic [2] |
| Calcification | Absent | Internal calcification, posterior acoustic shadowing [2] |
| Vascularity | Absent | Central vascularity [2] |
Mnemonic for suspicious USG features: "SHIT CME" — same features as suspicious thyroid nodules [3]: Solid, Hypoechoic, Irregular margins, Taller-than-wide, Calcification (micro), Microlobulation, Extra-thyroidal extension (in breast: chest wall invasion)
USG for nipple discharge specifically:
- Look for a dilated duct with intraluminal mass (papilloma)
- Look for a retroareolar abscess cavity (periductal mastitis/abscess)
- Look for a solid retroareolar mass (carcinoma)
- Characterise any cyst: simple (anechoic, posterior enhancement) vs complex (internal echoes, septations, solid component)
Limitations [3]:
- NOT useful as screening — operator-dependent
- Cannot pick up most calcifications [3] — mammography is far superior for detecting microcalcifications (DCIS)
The Breast Imaging Reporting and Data System (BI-RADS) is a standardised scoring system applicable to both mammographic and ultrasound findings [2]. It translates imaging findings into a management recommendation:
| BI-RADS Category | Assessment | Malignancy Risk | Management |
|---|---|---|---|
| 0 | Incomplete — needs additional imaging | N/A | Recall for additional views, USG, or comparison with prior studies |
| 1 | Negative — normal | ~0% | Routine screening |
| 2 | Benign finding | ~0% | Routine screening |
| 3 | Probably benign | ≤ 2% | Short-interval follow-up (6 months) |
| 4a | Low suspicion | > 2% to ≤ 10% | Tissue diagnosis (biopsy) [3] |
| 4b | Moderate suspicion | > 10% to ≤ 50% | Tissue diagnosis [3] |
| 4c | High suspicion | > 50% to < 95% | Tissue diagnosis [3] |
| 5 | Highly suggestive of malignancy | ≥ 95% | Tissue diagnosis [3] |
| 6 | Known biopsy-proven malignancy | N/A | Surgical excision when clinically appropriate [3] |
BI-RADS in Practice
BI-RADS 1–2: reassure and return to routine screening. BI-RADS 3: short-interval follow-up (6 months, then repeat). BI-RADS 4–5: biopsy is mandatory. BI-RADS 6: already proven cancer, imaging done for treatment planning. The key threshold is BI-RADS 4 — anything ≥ 4 gets a needle.
"Ductography" → ductus = duct + graphein = to write/record. It is a contrast study of the lactiferous duct system.
- Technique: A fine cannula is inserted into the discharging duct orifice on the nipple, and water-soluble contrast is injected. Mammographic images are then taken to outline the duct anatomy.
- Purpose: Localise an intraductal lesion (papilloma, DCIS) before surgical duct excision (microdochectomy) [2][3].
- Findings:
- Filling defect = intraluminal mass (papilloma or carcinoma)
- Duct irregularity or cut-off = possible malignancy
- Duct ectasia = dilated ducts without filling defects
- Limitations: Invasive, uncomfortable, technically difficult if duct cannot be cannulated, largely being replaced by breast MRI and ductoscopy.
- Technique: A microendoscope (0.5–1.2 mm diameter) is inserted into the discharging duct to directly visualise the duct lumen.
- Purpose: Direct visualisation of intraductal pathology (papilloma, DCIS); can take biopsies under direct vision; helps guide microdochectomy [2].
- Advantage: Combines diagnosis and surgical planning in one procedure.
- Limitation: Not widely available; technically challenging; limited to larger ducts.
- When? Not routine for nipple discharge, but useful in specific scenarios:
- Occult lesion (mammogram and USG negative but clinical suspicion high)
- Assessment of extent of disease in known malignancy (multifocal/multicentric disease)
- Screening high-risk patients (BRCA carriers)
- Evaluation of response to neoadjuvant chemotherapy
- Advantage: Highest sensitivity (~95–100%) for invasive breast cancer; not limited by breast density.
- Limitation: Low specificity (many false positives → unnecessary biopsies); expensive; requires IV gadolinium; not good for calcifications.
4C. Pathological Assessment
This is the definitive diagnostic step — imaging tells you something is there, but only tissue diagnosis tells you what it is.
- Technique: A fine needle (21–23 gauge) is inserted into the lesion (palpable or USG-guided) and cells are aspirated for cytological examination.
- Advantage: no need for local anaesthesia, smaller needle [3]
- Disadvantage: cannot assess architecture (i.e. cannot distinguish carcinoma in-situ from invasive carcinoma) [3] — Why? Because FNAC harvests individual cells, not tissue with preserved structure. You cannot tell whether cells have breached the basement membrane.
- Preferred if low risk (e.g. non-palpable mass, equivocal mammogram) or simple cysts [3]
FNAC approach to cystic lesions [3]:
- Lump disappears / clear fluid obtained → no further investigation
- Residual thickening / blood-stained fluid → core biopsy [3]
FNAC approach to solid lesions [3]:
- Benign cytology → observe or excision
- Atypical cytology → core needle biopsy (upgrade to histology)
- Malignant cytology → treat as cancer [3]
FNAC of nipple discharge (discharge cytology):
- Collect the discharge and send for cytology
- Can identify malignant cells, papillary fragments, inflammatory cells, or foamy macrophages (duct ectasia)
- Low sensitivity — a negative cytology does NOT exclude malignancy
- Useful as an adjunct, not a standalone investigation [3]
- Technique: A larger needle (9–14 gauge) with a spring-loaded cutting mechanism obtains a core of tissue, preserving architecture.
- Performed if BI-RADS ≥ 4 [3]
- Advantages: architectural assessment, tumour grading, receptor status (ER/PR/HER2) [3] — Why better than FNAC? Because a tissue core preserves the relationship between cells and basement membrane, allowing you to determine invasion vs in-situ, grade the tumour, and perform immunohistochemistry.
- Disadvantages: requires local anaesthesia, larger needle (9–14G) [3]
- For non-palpable masses: USG-guided, stereotactic (mammographic-guided), tomosynthesis (3D mammogram), or MRI-guided [3]
- Increased yield: vacuum-assisted core biopsy (VAB) — uses suction to obtain larger, more representative tissue samples [3]
Core biopsy for nipple discharge:
- If imaging identifies a mass lesion (papilloma, suspicious lesion) → USG-guided core biopsy
- If imaging shows microcalcifications without a mass → stereotactic (mammographic-guided) core biopsy
Core biopsy for nipple inversion:
- If a retroareolar mass is identified → USG-guided core biopsy
- If Paget's disease is suspected → full-thickness wedge biopsy of the nipple and underlying breast tissue [2]
- When? When core biopsy reveals a suspicious lesion that is not diagnostic, or when there is discordance between clinical/radiological and pathological findings [3].
- If atypical hyperplasia (ADH/ALH) is found on core biopsy → excisional biopsy MUST be performed to rule out adjacent malignancy [3][6] — Why? Because ADH/ALH on core biopsy is upgraded to DCIS or invasive cancer in ~15–30% of cases when the entire lesion is excised. The core only samples a small part of the lesion.
Localisation of non-palpable lesions for excisional biopsy [3]:
- Hook-wire localisation (HWL): a wire with a hook is inserted under imaging guidance to mark the lesion; surgeon excises tissue around the wire tip
- Problems: extensive normal tissue removal, wire outside skin, risk of broken wire [3]
- Radioactive seed localisation (RSL): ¹²⁵I-labelled titanium seed inserted 0–5 days prior to surgery [3]
- Radio-opaque lesion localisation (ROLL): ⁹⁹ᵐTc-labelled albumin-based colloid injected within 24 hours of surgery [3]
- Magseed localisation: non-radioactive magnetic seed [3]
- On-table USG: real-time ultrasound guidance during surgery [3]
5. Additional Investigations for Specific Causes
| Investigation | Why? | Key Findings |
|---|---|---|
| Serum prolactin | Confirm hyperprolactinaemia | Elevated ( > 25 µg/L in females); very high levels ( > 200 µg/L) suggest macroprolactinoma |
| TFTs (TSH, free T4) | Hypothyroidism causes ↑ TRH → ↑ prolactin; also ↓ clearance | ↑ TSH, ↓ fT4 |
| Renal function (urea, creatinine) | CKD → ↓ clearance of prolactin | Elevated urea/creatinine |
| Drug history review | Drug-induced hyperprolactinaemia | Antipsychotics, antiemetics, antidepressants |
| MRI pituitary (with gadolinium) | Exclude prolactinoma or other pituitary/hypothalamic lesions | Microadenoma ( < 10 mm) or macroadenoma (≥ 10 mm) |
| Visual field testing | Macroadenoma may compress the optic chiasm | Bitemporal hemianopia |
| Investigation | Why? | Key Findings |
|---|---|---|
| USG breast | Confirm abscess cavity; guide aspiration | Hypoechoic collection with posterior acoustic enhancement |
| Aspiration + culture | Identify organism and sensitivities | S. aureus (lactational); mixed flora (periductal) |
| Clinical diagnosis | Lactational mastitis is a clinical diagnosis; laboratory tests are not needed [2] | Imaging if refractory to antibiotics in 48–72 hours |
| Investigation | Why? | Key Findings |
|---|---|---|
| Full-thickness wedge biopsy of nipple | Definitive diagnosis | Paget cells — large, pale, malignant intraepithelial adenocarcinoma cells within the nipple epidermis [2][7] |
| Mammography (mandatory) | Detect underlying breast cancer, exclude synchronous cancers | Mass, microcalcifications, architectural distortion [2] |
| USG | Evaluate any palpable mass or mammographic abnormality | Guide core biopsy of underlying lesion [2] |
| Investigation | Why? | Key Findings |
|---|---|---|
| Bilateral mammogram | Exclude synchronous contralateral breast cancer [3] | Second primary or metastatic lesion |
| Bloods: LFT | Liver metastasis [3] | Elevated ALP, GGT, transaminases |
| Bloods: CaPO4 | Bone metastasis [3] | Hypercalcaemia |
| Tumour markers: CA15.3, CEA | Baseline for monitoring treatment response [3] | Elevated |
| CXR | Lung metastasis | Pulmonary nodules, pleural effusion |
| PET-CT, bone scan | Staging for distant metastasis [3] | Skeletal hot spots (bone scan); FDG-avid lesions (PET) |
| Diagnosis | Mammography | USG | Ductography | Pathology |
|---|---|---|---|---|
| Intraductal papilloma | Often normal; may show retroareolar soft-tissue density | Dilated duct with intraluminal solid mass; vascularity on Doppler | Filling defect within a single duct [2] | Papillary architecture with fibrovascular core on core biopsy [2] |
| Duct ectasia | Dilated calcified ducts [4]; tubular densities; periductal calcification (linear, branching but coarse) | Dilated anechoic or hypoechoic subareolar ducts; may show intraluminal debris | Dilated ducts without discrete filling defect | Plasma cells on cytology [4]; dilated ducts with chronic inflammation and fibrosis on histology |
| DCIS | Microcalcifications (pleomorphic, clustered, linear branching) [2][6] — this is the hallmark; may have no mass | May be occult on USG; if visible, irregular hypoechoic area | Duct irregularity or cut-off | Malignant cells within TDLU without invasion; comedo necrosis with dystrophic calcification (high-grade) [6] |
| Invasive carcinoma | Spiculated mass, architectural distortion, pleomorphic microcalcifications [2][3] | Hypoechoic, taller-than-wide, irregular/spiculated margins, posterior acoustic shadowing, central vascularity [2] | Duct obstruction, filling defect | Invasive malignant cells breaching basement membrane; receptor status (ER/PR/HER2) on core biopsy [3] |
| Paget's disease | Must look for underlying mass/calcifications [2] | Evaluate underlying mass | N/A | Paget cells in nipple epidermis [2][7]; underlying DCIS or invasive cancer |
| Fibrocystic changes | Dense parenchyma; scattered calcifications (usually benign-type: round, uniform) | Small cysts, areas of parenchymal thickening | N/A | Stromal fibrosis, micro/macrocysts, apocrine metaplasia, hyperplasia [2] |
| Lactational mastitis / abscess | Usually not performed (young, lactating) | Hypoechoic collection (abscess cavity) with posterior enhancement; surrounding oedema | N/A | Clinical diagnosis [2]; aspiration yields pus |
| Periductal mastitis | May show retroareolar density | Retroareolar abscess; fistula tract | N/A | Mixed inflammatory infiltrate; duct damage |
| Fat necrosis | Mimics CA radiologically — spiculated mass, calcification → core biopsy to differentiate [4] | Complex cystic/solid lesion; oil cyst | N/A | Lipid-laden macrophages, fibrosis, necrotic fat |
| Galactorrhoea | Normal breast | Normal breast | N/A | N/A (no breast pathology) — the issue is systemic/hormonal |
8. Approach to the Specific Complaint — Putting It All Together
- History and examination → classify discharge (physiological vs pathological)
- If milky bilateral → serum prolactin, TFTs, renal function, drug review → if prolactin elevated → pituitary MRI
- If pathological (spontaneous, unilateral, single-duct, serous/bloody):
- BI-RADS ≥ 4 → core needle biopsy [3]
- BI-RADS < 4 but persistent pathological discharge → ductogram or ductoscopy to localise lesion → microdochectomy (diagnostic and therapeutic) [2]
- If discharge resolves and imaging is benign → follow-up
- Nipple discharge cytology can be sent as adjunct but has low sensitivity — do not rely on it to exclude malignancy [3]
- Determine congenital vs acquired (history of onset, bilateral vs unilateral, evertibility)
- If congenital → reassure
- If acquired → mammogram + USG (exclude mass, microcalcifications)
- If mass identified → core biopsy
- If no mass but clinical suspicion → MRI breast or surgical exploration
- If inflammatory cause identified → treat accordingly (antibiotics, drainage, fistulectomy)
High Yield Summary — Diagnosis
-
Triple Assessment (Clinical + Radiological + Pathological) = sensitivity 99.6%, specificity 93% [1][8]. Positive if ANY one component is positive. Negative only when ALL three are negative.
-
Pathological discharge criteria: spontaneous, unilateral, single-duct, serous or bloody → mandates full triple assessment.
-
Mammogram for age ≥ 35; USG for all patients; USG first-line for age < 35 or pregnant/lactating [2][3].
-
BI-RADS ≥ 4 → core needle biopsy is mandatory [3]. BI-RADS 3 → short-interval follow-up.
-
Core biopsy > FNAC because it provides architectural assessment, grading, and receptor status (ER/PR/HER2). FNAC cannot distinguish in-situ from invasive cancer.
-
If ADH/ALH on core biopsy → excisional biopsy is MANDATORY to exclude adjacent malignancy (upgrade rate 15–30%) [3][6].
-
Ductography/ductoscopy help localise intraductal lesions when imaging is inconclusive but discharge is persistent.
-
Paget's disease diagnosis: full-thickness wedge biopsy of nipple showing Paget cells. Mammography is mandatory to find the underlying cancer.
-
Galactorrhoea workup: serum prolactin → TFTs → renal function → drug history → pituitary MRI if prolactin elevated.
-
Acquired unilateral nipple inversion → triple assessment to exclude malignancy, regardless of whether discharge is present.
Active Recall - Diagnostic Approach to Nipple Discharge and Inversion
References
[1] Lecture slides: GC 181. Breast mass breast cancer; benign breast diseases; mammography; breast cancer screening.pdf (p10, p12, p15, p16) [2] Senior notes: felixlai.md (Nipple discharge and inversion pp.269–271; Duct ectasia p.280; Mammogram and USG findings pp.288–290; Paget's disease pp.286–287; Intraductal papilloma p.276; ADH/ALH pp.274–275) [3] Senior notes: maxim.md (Sections 8.2–8.4: Triple assessment, radiological assessment, pathological assessment pp.178–183; BI-RADS classification p.181; Excisional biopsy and localisation techniques pp.182–183) [4] Senior notes: maxim.md (Section 8.5: Inflammatory breast conditions — duct ectasia, fat necrosis pp.185–186) [5] Senior notes: maxim.md (Section 8.6: Benign breast tumours p.187) [6] Senior notes: maxim.md (Section 8.4: DCIS vs LCIS table p.184; ADH on core biopsy → excisional biopsy p.183) [7] Lecture slides: GC 201. Skin ulcers skin and subcutaneous lesions; skin cancer.pdf (p47) [8] Lecture slides: The Managment of breast cancer_Prof A Kwong 20_2_2020.pdf (p10)
Management Algorithm and Treatment Modalities
The management of nipple discharge and nipple inversion is cause-directed. There is no single treatment — the approach depends entirely on what the triple assessment reveals. Think of it as a decision tree: first you identify the underlying cause, then you treat that cause. The nipple discharge or inversion is the symptom, not the disease.
The key management principle is straightforward:
- Physiological / benign discharge → reassure, address the underlying cause (e.g. stop offending drug, treat prolactinoma)
- Pathological discharge → surgical excision of the offending duct (diagnostic AND therapeutic)
- Malignancy → treat as breast cancer (surgery ± adjuvant therapy)
- Infection/inflammation → antibiotics ± drainage
- Congenital nipple inversion → reassure; surgical correction only if functional/cosmetic concern
- Acquired nipple inversion → treat the underlying cause
2. Management by Underlying Cause — Detailed Treatment Modalities
2A. Galactorrhoea (Milky Bilateral Discharge)
The discharge itself is not the problem — the underlying hormonal derangement is.
| Cause | Treatment | Mechanism | Notes |
|---|---|---|---|
| Prolactinoma | Bromocriptine or Cabergoline [2] | Dopamine agonists → activate D2 receptors on lactotroph cells → restore tonic inhibition of prolactin secretion → prolactin drops → galactorrhoea resolves | Cabergoline is preferred in practice (longer half-life, better tolerated, twice weekly dosing). Bromocriptine ("bromo" = bad smell — patients hate the nausea) requires daily dosing. |
| Drug-induced | Reassurance and continuation of drug OR taper or change medication [2] | Remove the D2-blocking agent → restore dopaminergic inhibition of prolactin | Always weigh the psychiatric/medical need for the drug vs the discharge. Often the answer is reassurance — galactorrhoea is not harmful. |
| Hypothyroidism | Levothyroxine | Corrects low T4 → normalises TRH → removes TRH-mediated prolactin stimulation; also restores metabolic clearance of prolactin | Galactorrhoea typically resolves within weeks of achieving euthyroid state |
| CKD | Optimise renal function; dialysis if indicated | Improves renal clearance of prolactin |
- Transsphenoidal resection [2]
- Indication 1: Refractory to dopamine agonists — prolactin does not normalise or tumour does not shrink [2]
- Indication 2: Women with giant lactotroph adenoma who wish to become pregnant — Why? If the patient becomes pregnant and discontinues the dopamine agonist during pregnancy (as is often recommended), a giant adenoma may enlarge to clinically significant size before delivery, causing mass effects (visual field defects, headaches) [2]
- The approach is "trans-sphenoidal" = through the sphenoid sinus, which sits just below the pituitary fossa — minimally invasive, avoids craniotomy
2B. Intraductal Papilloma
Treatment: Microdochectomy — excision of the diseased duct, usually guided by ductogram / ductoscopy [1][2][5]
- "Micro" = small, "docho" = duct (from Greek dochos), "ectomy" = excision. Literally: excision of a single small duct.
- What it involves: Excision of the single affected lactiferous duct and its associated lobules [2]
- Why it is the standard: It is both diagnostic (the entire duct is sent for histology, excluding DCIS or IDC that may be lurking behind the papilloma) and therapeutic (removes the source of discharge)
- Guidance: Usually guided by ductogram or ductoscopy [1][2] — a probe or wire is placed in the discharging duct to guide the surgeon to the correct duct
- Indication: Persistent spontaneous discharge from a single duct [2]; or biopsy-proven papilloma [2]
- Technique: A periareolar incision is made, the discharging duct is identified (often by injecting dye or passing a lacrimal probe), and the duct with its associated lobule is excised en bloc
- Contraindication: Not appropriate if malignancy is strongly suspected (proceed to oncological surgery instead)
- What it involves: Excision of all retroareolar (major) ducts [2]
- Indication: Persistent spontaneous discharge when the offending duct cannot be identified (multi-duct discharge); or recurrent discharge after microdochectomy [2]
- Consequence: Loss of ability to breastfeed from the affected breast (all major ducts removed), so it is not first-line in young women who wish to breastfeed
- Also indicated: As part of treatment for periductal mastitis with periareolar fistula (total duct excision ± fistulectomy) [2]
Microdochectomy vs Major Duct Excision
Microdochectomy = single duct removed → first-line for single-duct pathological discharge (usually papilloma). Major duct excision = all ducts removed → for multi-duct discharge, recurrent discharge, or when the offending duct cannot be localised. Both are diagnostic and therapeutic — the tissue is always sent for histology.
2C. Duct Ectasia
Conservative management only — this is a benign, hormone-driven process:
| Treatment | Mechanism | Notes |
|---|---|---|
| Avoid caffeine [4] | Methylxanthines in caffeine may stimulate fibrocystic proliferation (controversial but commonly advised) | Some patients report improvement |
| Evening primrose oil [4] | Contains gamma-linolenic acid (GLA) → modulates prostaglandin synthesis → may reduce breast pain | Evidence is weak but widely used |
| Analgesics (NSAIDs) [4] | Anti-inflammatory and analgesic effect | For cyclical mastalgia |
| COC (combined oral contraceptives) [4] | Suppresses the cyclical hormonal fluctuations (oestrogen and progesterone peaks) that drive fibrocystic changes | Stabilises the hormonal environment |
| Breast cyst aspiration | If a dominant cyst is present, FNAC drains the fluid and the lump disappears | Surgery only if recurrent or blood-stained aspirate or solid component present [4] |
2E. Malignancy (DCIS, IDC, Paget's Disease)
When malignancy is the cause of nipple discharge or inversion, the management follows standard breast cancer protocols. Below is a focused summary relevant to these presentations.
- Treatment should include excision of the underlying cancer and the nipple-areolar complex [2]
- Both mastectomy or BCT followed by whole-breast irradiation are acceptable treatment options [2]
- Nipple-areolar sparing mastectomy is CONTRAINDICATED in Paget's disease [9][3] — because the disease involves the nipple epidermis; preserving it would leave tumour behind
- Why BCT is acceptable: If the underlying cancer is small and amenable to wide local excision, the nipple-areolar complex is excised along with the tumour, followed by whole-breast radiotherapy. Cosmesis is poor (no nipple), but oncological outcomes are equivalent to mastectomy.
Management depends on the Van Nuys Prognostic Index [2]:
| Score | Treatment |
|---|---|
| Low score | Wide local excision alone [2] |
| Intermediate score | Wide local excision + adjuvant radiotherapy [2] |
| High score | Mastectomy [2] |
Key surgical principles:
- Negative resection margins ≥ 2 mm [2] — Why 2 mm? DCIS is famous for "skip lesions" (discontinuous spread along ducts), so a wider margin reduces recurrence. The older 10 mm margin has been abandoned as overly aggressive [2].
- Sentinel lymph node biopsy (SLNB) may be considered for DCIS with planned mastectomy or suspicious features — Why? Because if a mastectomy specimen incidentally reveals invasive cancer, SLNB cannot be performed after mastectomy (lymphatic drainage patterns are permanently altered) [2]
- ALND is NOT indicated for pure DCIS — DCIS by definition does not invade and therefore cannot metastasise to lymph nodes [2]
- Adjuvant hormonal therapy: ER-positive DCIS benefits from tamoxifen (reduces recurrence risk and contralateral cancer risk, but no survival benefit) [2]
- No adjuvant chemotherapy for DCIS (no added benefit) [2]
The full breast cancer management is beyond the scope of nipple discharge notes, but the key decision tree for the breast is:
Breast Management:
| Option | Approach | Key Points |
|---|---|---|
| Breast-conserving surgery (BCS) / wide local excision (WLE) | Excise tumour with negative margins + compulsory adjuvant radiotherapy [2][3] | Negative margin = "no ink on tumour" [3]; positive margin = > 2× increase in ipsilateral breast tumour recurrence [3] |
| Mastectomy | When BCS is contraindicated or patient preference [3] | Similar efficacy to BCS + RT [3] |
Contraindications to BCS (must know!) [3]:
- Multicentric disease (≥ 2 primary tumours in separate quadrants)
- High tumour-to-breast ratio > 20% (can be downstaged by neoadjuvant chemotherapy)
- Tumour too close to NAC
- Persistent positive resection margin
- Diffuse malignant-appearing calcifications on imaging
- Inflammatory breast cancer
Contraindications to radiotherapy [3]:
- History of RT to affected chest wall / breast
- Pregnancy (possible to perform BCS in 3rd trimester and defer RT until after delivery)
- Connective tissue disease (e.g. scleroderma, Sjögren's disease) — poor skin healing, risk of fistula formation
- Modified radical mastectomy: whole breast + overlying skin + axillary LN (level I + II) [3]
- Simple mastectomy: clinically node-negative; axillary LN not dissected → SLNB performed [3]
- Skin-sparing mastectomy: preserves overlying breast skin; C/I if inflammatory breast cancer [3][9]
- Nipple-areolar sparing mastectomy: preserves NAC dermis/epidermis with removal of major ducts from nipple lumen [2][9]. C/I: inflammatory breast cancer, involvement of NAC, nipple retraction, Paget's disease [3][9]. For selective low-risk patients; no nipple involvement of cancer; prophylactic mastectomy [9]
Axillary Management:
| Scenario | Management |
|---|---|
| Clinically node-negative | Sentinel lymph node biopsy (SLNB) [3] |
| Clinically node-positive (by palpation / USG) | Axillary lymph node dissection (ALND) [3] |
| SLNB: no metastasis or micrometastasis (≤ 2 mm) | No further axillary dissection [3] |
| SLNB: macrometastasis ( > 2 mm) in 1–2 LN | Controversial — may omit ALND if receiving breast RT [3] |
| SLNB: macrometastasis in ≥ 3 LN or extranodal extension | ALND [3] |
Adjuvant Systemic Therapy — based on St Gallen's IHC subtyping [3]:
| IHC Subtype | Definition | Adjuvant Therapy |
|---|---|---|
| Luminal A | HR+/HER2-/Ki67 low | Endocrine therapy alone [3] |
| Luminal B | HR+/HER2-/Ki67 high | Endocrine therapy ± cytotoxic chemotherapy [3] |
| Luminal B (HER2+) | HR+/HER2+ | Cytotoxics + anti-HER2 + hormonal therapy [3] |
| HER2-positive | HR-/HER2+ | Cytotoxics + anti-HER2 therapy [3] |
| Triple-negative | HR-/HER2- | Cytotoxic therapy [3] |
Why Is This Relevant to Nipple Discharge?
Paget's disease of the nipple is almost always associated with HER2-positive breast cancer. This means the adjuvant treatment will typically include anti-HER2 therapy (trastuzumab) in addition to surgery. When you see Paget's, think HER2+, think trastuzumab.
2F. Lactational Mastitis (± Puerperal Breast Abscess)
| Treatment | Mechanism | Key Points |
|---|---|---|
| Symptomatic relief | NSAIDs or cold compress [2] | Analgesic and anti-inflammatory |
| Breastfeeding optimisation | Complete emptying with pumping or hand expression [2] | Removes stagnant milk — the growth medium for bacteria |
| Does NOT require stopping breastfeeding [2][4] | Counter-intuitive but essential — continued breastfeeding/pumping prevents engorgement and maintains milk flow | |
| Antibiotics | 1st generation cephalosporin (cephalexin) or dicloxacillin [2] | Covers S. aureus (most common pathogen); cloxacillin also mentioned [4] |
- Abscess = failure to respond to antibiotics, USG evidence of abscess cavity, or aspiration of pus [2]
- Needle aspiration (USG-guided) — when overlying skin is normal (not ischaemic) [2]
- Surgical drainage (incision and drainage, I&D) — when there is ischaemia or pressure necrosis of overlying skin, or when abscess is not responsive to antibiotics and needle aspiration [2]
This condition is notoriously recurrent, especially in smokers. The management escalates depending on severity:
| Stage | Treatment | Details |
|---|---|---|
| Uncomplicated periductal mastitis | Empirical antibiotics | Amoxicillin-clavulanate (Augmentin) OR Dicloxacillin + Metronidazole [2]. Why Metronidazole? Because the flora is mixed aerobic-anaerobic (Bacteroides is anaerobic), and Metronidazole covers anaerobes |
| Subareolar abscess | Antibiotics + abscess drainage | USG-guided fine needle aspiration OR incision and drainage (I&D) [2] |
| Periareolar fistula | Fistulectomy + primary closure with antibiotic coverage ± total duct excision | OR lay open the fistula to allow it to granulate ± total duct excision [2]. Total duct excision is added because the underlying diseased ducts are the source of recurrence — if you just close the fistula without removing the ducts, it recurs |
| Smoking cessation | Essential for preventing recurrence | Smoking is the major modifiable risk factor — it damages duct epithelium, promotes squamous metaplasia, and drives the entire disease process |
A self-limiting disease that resolves slowly over 9–12 months, but can be extremely distressing [2].
| Treatment | Indication | Notes |
|---|---|---|
| NSAIDs | Localised pain [2] | First-line symptomatic management |
| Amoxicillin-clavulanate (Augmentin) | If Corynebacterium infection is recovered from biopsy [2] | Doxycycline for penicillin allergy |
| Corticosteroids ± Methotrexate (MTX) | Patient unresponsive to NSAIDs or antibiotics [2] | Reduces swelling but may not alter the natural history; discontinuation/tapering is associated with rebound inflammation [2] |
| Surgical excision: NOT recommended | — | Surgical excision of IGM is often followed by slow wound healing [2] |
IGM — Don't Operate!
IGM is one of those conditions where surgery makes things worse. The granulomatous tissue heals poorly, wounds break down, and you end up with a bigger problem than you started with. Patience + NSAIDs + steroids if needed. It will eventually resolve.
- Reassurance — this is benign, bilateral, and has no malignancy risk
- Breastfeeding: Grade 1 inversion (easily evertible) is usually compatible with breastfeeding. Grade 2–3 may require nipple shields or breast pumps to help with latch
- Surgical correction (if desired for cosmetic/functional reasons):
- Various techniques exist (e.g. purse-string suture, duct division, dermal flaps)
- Trade-off: duct division corrects inversion but sacrifices the ability to breastfeed from that breast
- Not medically necessary — purely a patient-preference decision
When nipple discharge leads to a biopsy finding of ADH or ALH, management shifts to cancer risk reduction and surveillance [2]:
| Treatment | Why? |
|---|---|
| Avoidance of OC pills and HRT | Removes exogenous oestrogen exposure, reducing the already 5× elevated cancer risk [2] |
| Yearly mammography | Detect any new malignancy early [2] |
| Twice-yearly breast examination | Clinical surveillance [2] |
| Hormonal therapy — SERMs (tamoxifen) or aromatase inhibitors | Chemoprevention — tamoxifen blocks oestrogen receptors in breast tissue, reducing proliferative stimulus; aromatase inhibitors (in postmenopausal women) block peripheral oestrogen synthesis [2] |
| Cause | First-Line Management | Second-Line / Surgical | Key Principle |
|---|---|---|---|
| Physiological lactation | Reassurance | — | Benign; will resolve |
| Galactorrhoea | Treat underlying cause (dopamine agonist, stop offending drug, levothyroxine) | Transsphenoidal surgery if refractory prolactinoma | Fix the hormonal problem |
| Intraductal papilloma | Microdochectomy (guided by ductogram/ductoscopy) [1] | Major duct excision if recurrent | Diagnostic + therapeutic |
| Duct ectasia | Conservative (resolves spontaneously) | Microdochectomy if persistent | NOT cancer risk; benign |
| Fibrocystic changes | Avoid caffeine, evening primrose oil, NSAIDs, COC | Cyst aspiration; surgery only if solid/recurrent | Hormonal; cyclical |
| DCIS | WLE ± RT (by Van Nuys score) or mastectomy | Tamoxifen if ER+; SLNB if planned mastectomy | Margins ≥ 2 mm |
| Invasive carcinoma | BCS + RT or mastectomy + axillary management | Adjuvant systemic therapy by IHC subtype | No ink on tumour |
| Paget's disease | Excision of underlying cancer + NAC | Mastectomy or BCT + RT | Nipple-sparing mastectomy C/I |
| Lactational mastitis | Antibiotics (cephalexin/dicloxacillin) + continue breastfeeding | Abscess: USG aspiration or I&D | Do NOT stop breastfeeding |
| Periductal mastitis | Augmentin or dicloxacillin + metronidazole | Abscess drainage; fistulectomy ± total duct excision | Smoking cessation essential |
| IGM | NSAIDs; Augmentin if Corynebacterium | Steroids ± MTX if refractory; do NOT operate | Self-limiting; surgery harms |
| ADH/ALH | Surveillance + avoid OC/HRT | Tamoxifen / aromatase inhibitors | 5× cancer risk; monitor |
| Congenital nipple inversion | Reassurance | Surgical correction if cosmetic/functional concern | Benign; no cancer risk |
| Acquired nipple inversion | Treat underlying cause | Depends on cause | Always exclude malignancy first |
| Procedure | What Is Excised | Indication | Key Points |
|---|---|---|---|
| Microdochectomy | Single lactiferous duct + associated lobules | Persistent spontaneous single-duct discharge [1][2]; biopsy-proven papilloma | Guided by ductogram/ductoscopy [1]; diagnostic + therapeutic; preserves other ducts |
| Major duct excision (Hadfield's) | All retroareolar ducts | Persistent spontaneous multi-duct discharge [2]; recurrent discharge; periductal mastitis with fistula | Sacrifices breastfeeding ability; removes all diseased ducts |
| Wide local excision (BCS) | Tumour with margin of normal tissue | Early breast cancer (≤ T2, single quadrant, appropriate tumour:breast ratio) | Compulsory adjuvant RT [2]; margin = "no ink on tumour" [3] |
| Simple mastectomy | Entire breast; axilla not dissected | Clinically node-negative [3][9] | SLNB performed simultaneously |
| Modified radical mastectomy | Whole breast + overlying skin + axillary LN (level I + II) | Clinically node-positive | More extensive than simple mastectomy [3] |
| Skin-sparing mastectomy | Breast tissue; preserves overlying skin and inframammary fold | Therapeutic with immediate reconstruction; prophylactic | C/I: inflammatory breast cancer [3][9] |
| Nipple-areolar sparing mastectomy | Breast tissue; preserves NAC dermis/epidermis; removes major ducts | Selective low-risk patients; no nipple involvement; prophylactic mastectomy [9] | C/I: inflammatory CA, NAC involvement, nipple retraction/discharge, Paget's disease [3][9] |
| Fistulectomy | Fistula tract ± total duct excision | Periareolar fistula from periductal mastitis | Combined with antibiotic coverage [2] |
| Transsphenoidal resection | Pituitary adenoma (prolactinoma) | Refractory to dopamine agonists; giant adenoma + pregnancy planned | Through sphenoid sinus; avoids craniotomy [2] |
| Treatment | Contraindication | Why? |
|---|---|---|
| BCS/WLE | Multicentric disease, high tumour:breast ratio, persistent positive margins, diffuse malignant calcifications, inflammatory breast cancer, tumour too close to NAC [3] | Cannot achieve adequate negative margins with acceptable cosmesis |
| Adjuvant RT | Prior RT to same area, pregnancy (defer to post-delivery), connective tissue disease (scleroderma, Sjögren's) [3] | Excessive cumulative radiation dose; teratogenicity; poor wound healing → fistula |
| Nipple-areolar sparing mastectomy | Inflammatory CA, Paget's disease, nipple retraction, nipple discharge, NAC involvement by cancer [3][9] | Leaving the NAC would leave residual tumour behind |
| Surgical excision for IGM | Essentially always contraindicated [2] | Slow wound healing — makes the problem worse [2] |
| Stopping breastfeeding in lactational mastitis | Does NOT require stopping breastfeeding [2][4] | Continued emptying prevents further engorgement and accelerates resolution |
High Yield Summary — Management
-
Microdochectomy (excision of the diseased duct, guided by ductogram/ductoscopy) [1] is the standard surgical treatment for pathological single-duct discharge (papilloma). Major duct excision is for multi-duct or recurrent discharge.
-
Galactorrhoea: treat the cause — dopamine agonists for prolactinoma (bromocriptine/cabergoline); stop offending drugs; levothyroxine for hypothyroidism. Transsphenoidal surgery if refractory or giant adenoma + pregnancy desired.
-
Duct ectasia: conservative first — often resolves spontaneously. Microdochectomy only if persistent.
-
Lactational mastitis: antibiotics (cephalexin/dicloxacillin) + continue breastfeeding + complete emptying. Abscess → USG aspiration or I&D.
-
Periductal mastitis: Augmentin or dicloxacillin + metronidazole. Abscess → drainage. Fistula → fistulectomy ± total duct excision. Smoking cessation is critical.
-
IGM: do NOT operate — slow wound healing. NSAIDs first, antibiotics if Corynebacterium, steroids ± MTX if refractory.
-
Paget's disease: excise underlying cancer + NAC. Nipple-sparing mastectomy is contraindicated.
-
DCIS: WLE with margins ≥ 2 mm ± RT (Van Nuys score) or mastectomy. SLNB if planned mastectomy. Tamoxifen if ER+. No chemotherapy.
-
Invasive carcinoma: BCS + compulsory RT or mastectomy; axillary management by SLNB/ALND; adjuvant systemic therapy by IHC subtype (St Gallen's).
-
Contraindications to BCS: multicentric disease, high tumour:breast ratio, persistent positive margins, diffuse malignant calcifications, inflammatory breast cancer.
Active Recall - Management of Nipple Discharge and Inversion
References
[1] Lecture slides: GC 181. Breast mass breast cancer; benign breast diseases; mammography; breast cancer screening.pdf (p9, p16, p19) [2] Senior notes: felixlai.md (Nipple discharge and inversion pp.269–271; Duct ectasia p.280; Lactational mastitis pp.280–281; Periductal mastitis pp.281–282; IGM pp.282–283; ADH/ALH pp.274–275; Intraductal papilloma p.276; Paget's disease pp.286–287; DCIS pp.291–293; BCT and mastectomy pp.298–302) [3] Senior notes: maxim.md (Sections 8.2–8.4: BCS contraindications, mastectomy types, axillary management, St Gallen's subtyping pp.183–186; Inflammatory conditions p.185; Fibrocystic changes p.186; ACP risk table p.182) [4] Senior notes: maxim.md (Section 8.5: Inflammatory and non-inflammatory breast conditions — mastitis, duct ectasia, fibrocystic changes pp.185–186) [5] Senior notes: maxim.md (Section 8.6: Benign breast tumours — intraductal papilloma p.187) [9] Lecture slides: The Managment of breast cancer_Prof A Kwong 20_2_2020.pdf (p38 — Types of mastectomy)
Complications of Nipple Discharge and Inversion
Complications in this context arise from two distinct angles: (1) complications of the underlying conditions themselves if untreated or under-recognised, and (2) complications of the treatments/procedures used to manage them. We will cover both systematically.
The key conceptual framework: nipple discharge and nipple inversion are symptoms, not diseases. So the complications we discuss are really the complications of what causes them (papilloma, duct ectasia, mastitis, carcinoma) and the complications of what we do about them (microdochectomy, major duct excision, mastectomy, ALND).
1. Complications of Underlying Conditions
| Complication | Mechanism | Why It Matters |
|---|---|---|
| Missed malignancy (DCIS → invasive carcinoma) | DCIS is a precursor to invasive ductal carcinoma at a rate of ~1%/year [2]. If pathological discharge caused by DCIS is dismissed as benign (e.g. attributed to duct ectasia without biopsy), the window for curative treatment of non-invasive disease is lost | This is the single most important complication — the entire reason we investigate pathological discharge is to catch malignancy early. DCIS caught and treated has an excellent prognosis; IDC that has spread to lymph nodes does not |
| Progression of intraductal papilloma | While a solitary papilloma is benign, multiple papillomas (papillomatosis) carry an increased risk of breast cancer. Without excision, the risk of missing concurrent atypia or DCIS within the papilloma is ~10–15% | This is why microdochectomy is both diagnostic and therapeutic — the excised duct is sent for full histological assessment |
| Psychological distress and anxiety | Persistent bloody or spontaneous discharge is extremely distressing for patients who worry about cancer | Even if benign, untreated discharge causes significant quality-of-life impairment |
| Complication | Mechanism |
|---|---|
| Periductal mastitis [2][4] | Blocked, dilated ducts provide a nidus for secondary bacterial infection → periductal inflammation. This is the most common complication of duct ectasia. Why does duct blockage cause infection? Stagnant inspissated secretions create a warm, nutrient-rich, stagnant environment ideal for bacterial colonisation |
| Breast abscess [4] | Periductal mastitis that progresses without adequate treatment → localised collection of pus (abscess). Abscess may be subareolar and initially non-fluctuant, making clinical detection tricky |
| Nipple retraction/inversion | Progressive periductal fibrosis from chronic inflammation → shortening of the duct → pulls the nipple inward. This is the mechanism of nipple inversion in duct ectasia [2] |
| Complication | Mechanism | Incidence |
|---|---|---|
| Breast abscess (puerperal) | Mastitis progresses to abscess formation in 25% of patients [2]. Organisms (S. aureus most commonly) continue to multiply in stagnant infected milk → walled-off collection of pus forms. Breast abscess occurs in late stage and is often NOT fluctuant — making clinical detection difficult [2] | 25% of untreated mastitis cases |
| Sepsis | Severe untreated mastitis with systemic spread → bacteraemia → septic shock. Rare but life-threatening | Rare |
| Cessation of breastfeeding | Pain, fear, and misinformation lead patients to stop breastfeeding prematurely. This paradoxically worsens engorgement and can worsen the mastitis. Does NOT require stopping breastfeeding [2] — continued emptying is therapeutic | Common |
| Recurrence | Incomplete antibiotic course or persistent breastfeeding difficulties (poor latch, incomplete emptying) | Common in first-time mothers |
| Complication | Mechanism |
|---|---|
| Subareolar abscess | Secondary bacterial infection of inflamed periductal tissue → abscess formation in the subareolar region. The mixed aerobic-anaerobic flora (Staphylococci, Bacteroides) makes this particularly aggressive [2] |
| Periareolar fistula | Secondary infection of inflamed ducts → duct damage and subsequent rupture → abscess formation → draining fistula (communication between a major subareolar duct and the skin) [2]. This is the hallmark chronic complication of periductal mastitis. A fistula will NOT heal on its own because the underlying diseased duct keeps producing secretions that feed the infection cycle |
| Recurrence | Extremely common, especially if the patient continues smoking. Smoking damages duct epithelium → squamous metaplasia → keratinous plugging → reinfection. Without smoking cessation, the cycle repeats |
| Nipple retraction | Chronic inflammation → progressive fibrosis → duct shortening → retraction [2] |
| Complication | Mechanism |
|---|---|
| Chronic draining sinuses | Granulomatous inflammation → tissue breakdown → sinus tracts to skin. These are notoriously slow to heal |
| Poor wound healing post-surgery | Surgical excision of IGM is often followed by slow wound healing [2]. The granulomatous tissue has poor vascularity and chronic inflammation that impairs normal wound healing processes |
| Rebound inflammation | Discontinuation or tapering of corticosteroids is associated with rebound inflammation [2]. The granulomatous process flares when the immunosuppressive effect of steroids is removed |
| Misdiagnosis as carcinoma | IGM mimics CA breast [2] clinically and radiologically. The complication here is unnecessary cancer treatment (mastectomy) for a benign, self-limiting condition — this is why core biopsy is essential |
If the underlying cause is malignancy and it is not caught early, the complications are those of advanced breast cancer:
| Complication | Mechanism | Clinical Features |
|---|---|---|
| Local invasion | Tumour invades Cooper's ligaments (skin tethering/dimpling), pectoralis fascia (fixation), dermal lymphatics (peau d'orange, inflammatory breast cancer) | Skin dimpling, peau d'orange, chest wall fixation [2] |
| Axillary lymphadenopathy | Metastatic spread via lymphatics to axillary lymph nodes | Hard, fixed, matted nodes [2] |
| Distant metastasis | Haematogenous spread to common sites | Bone (back pain), liver (jaundice, hepatomegaly), lung (dyspnoea, cough), brain (headache, neurological deficits) [2] |
| Locally advanced disease | Neglected cancer → skin ulceration, fungation, pain | Quality of life devastation |
2. Complications of Treatment
These are relatively minor procedures, but complications can still occur:
| Complication | Mechanism | Notes |
|---|---|---|
| Wound infection | Bacterial contamination of the periareolar incision | Uncommon; managed with antibiotics |
| Haematoma | Bleeding from divided vessels in the retroareolar space | Small haematomas resorb; large ones may need evacuation |
| Nipple necrosis | Disruption of blood supply to the nipple-areolar complex during dissection | Rare in microdochectomy (only one duct dissected); more common in major duct excision where all retroareolar tissue is dissected |
| Altered nipple sensation | Division of small sensory nerve branches around the nipple | Common; usually transient, but can be permanent |
| Loss of ability to breastfeed | Microdochectomy: loss of one duct segment (minimal impact on overall lactation). Major duct excision: loss of ALL ducts (complete loss of breastfeeding ability on that side) | Important to counsel young women who wish to breastfeed in the future |
| Nipple inversion (iatrogenic) | Removal of subareolar tissue leaves a void → scar contracture pulls the nipple inward | Paradoxically, the treatment for discharge can cause the inversion you were trying to evaluate |
| Recurrence of discharge | Incomplete excision of the diseased duct, or pathology in a different duct system | Major duct excision is the fallback if microdochectomy fails |
| Cosmetic deformity | Volume loss in the retroareolar area after excision of duct tissue | Usually minimal for microdochectomy; more noticeable for major duct excision |
When nipple discharge or inversion leads to a diagnosis of breast cancer requiring mastectomy, the complications are:
General complications [2]:
- Wound infection
- Bleeding and haematoma
- Anaesthetic complications
Specific complications [2][3]:
| Complication | Mechanism | Management |
|---|---|---|
| Seroma | Collection of serous fluid in the dead space created by removal of breast tissue and disruption of lymphatics. Untreated seroma results in delayed wound healing, wound infection and dehiscence, flap necrosis and poor cosmetic outcomes [2] | Insertion of drains (Jackson-Pratt drain) or percutaneous aspiration [2][3]. Drains removed when output < 30 mL/day × 2 days [3] |
| Skin flap necrosis | Ischaemia of the thin skin flaps created during mastectomy — the blood supply to the flap edges may be compromised, especially if flaps are thin or tension is excessive | Full-thickness skin flap necrosis requires surgical debridement and may require skin grafting [2] |
| Post-mastectomy pain syndrome | Burning, aching and tight constriction of axilla, upper arm and chest wall [2]. Caused by damage to intercostal nerves, intercostobrachial nerve, and chest wall trauma. Neuropathic in nature | Chronic pain management: gabapentin/pregabalin, physiotherapy |
| Phantom breast syndrome | Change in chest wall sensation; exact cause unknown [2]. Analogous to phantom limb pain — the brain's cortical representation of the breast persists even after removal. May persist years after surgery [3] | Difficult to treat; psychological support, neuropathic pain agents |
| Arm morbidity | Includes arm or shoulder pain, swelling, numbness, stiffness [2]. Caused by surgical disruption of axillary structures, lymphatic channels, and nerves | Physiotherapy, pneumatic compression (for lymphoedema) |
| Skin flap / NAC necrosis (if reconstruction) [3] | Compromised blood supply to preserved skin or NAC during skin-sparing or nipple-sparing mastectomy | Debridement; may need revision surgery |
| Frozen shoulder [3] | Post-operative immobilisation and pain lead to adhesive capsulitis of the shoulder joint | Early physiotherapy and mobilisation are essential |
Axillary surgery is performed when nipple discharge or inversion is caused by malignancy and axillary staging is needed.
Axillary dissection: removal of level I and II lymph nodes, pectoralis minor as the landmark. Preservation of (special caution to): long thoracic nerve, thoracodorsal nerve, intercostobrachial nerves [1]
Complications: lymphoedema (up to 10–20% risk), nerve injuries, general surgical complications (skin infection, scar etc), frozen shoulder [1]
| Complication | Nerve/Structure Injured | Clinical Result | Why? |
|---|---|---|---|
| Lymphoedema [1][3] | Disruption of axillary lymphatic channels | Chronic swelling of the ipsilateral arm; can be progressive and debilitating | Lymph from the arm normally drains through axillary nodes → removing these nodes disrupts drainage → lymph fluid accumulates in the arm. Up to 10–20% risk [1]. Management: pneumatic compression device [3] |
| Winged scapula [1][3] | Long thoracic nerve injury | Medial border of scapula protrudes posteriorly; inability to abduct arm above 90° | The long thoracic nerve innervates serratus anterior, which holds the scapula against the chest wall. If denervated → scapula "wings" off the chest wall during arm elevation |
| Weak shoulder adduction and internal rotation [1][3] | Thoracodorsal nerve injury | Weakness of latissimus dorsi → difficulty pulling arm downward and inward | The thoracodorsal nerve innervates latissimus dorsi. Injury → weak adduction and internal rotation of the shoulder |
| Loss of pectoralis major function [3] | Medial pectoral nerve injury | Weakness/atrophy of pectoralis major | The medial pectoral nerve innervates the pectoralis major. This nerve runs medially to pec minor and can be injured during level II dissection |
| Paraesthesia of axilla, medial arm, and lateral chest wall [1][3] | Intercostobrachial nerve injury | Numbness or tingling sensation in the distribution of T2 dermatome (medial arm, axilla, lateral chest) | The intercostobrachial nerve is a cutaneous branch of T2 that crosses the axilla. It is frequently sacrificed during ALND. The sensory loss is permanent but not disabling |
| Seroma [3] | Disruption of lymphatic channels in axilla | Fluid collection in the axilla | Managed by aspiration or drain placement |
| Upper limb lymphangiosarcoma (Stewart-Treves syndrome) [3] | Chronic lymphoedema → malignant transformation of lymphatic endothelial cells | Rare but devastating angiosarcoma of the chronically oedematous arm, typically appearing 5–15 years after surgery | Very rare; the chronic stagnation and impaired immune surveillance in oedematous tissue allow malignant transformation |
Four Nerves at Risk in ALND — Must Know!
In any exam question about axillary surgery complications, you need to name these four nerves and what happens when each is injured:
- Long thoracic nerve → serratus anterior → winged scapula
- Thoracodorsal nerve → latissimus dorsi → weak adduction and internal rotation
- Medial pectoral nerve → pectoralis major → weak arm flexion/adduction
- Intercostobrachial nerve → T2 cutaneous sensation → paraesthesia of axilla, medial arm, lateral chest wall
The intercostobrachial nerve is most commonly injured because it directly crosses the operative field.
When mastectomy is performed for breast cancer presenting with nipple discharge or inversion, reconstruction may be offered. Complications depend on the reconstruction method:
Autologous tissue reconstruction [2]:
| Flap Type | Key Complication | Why? |
|---|---|---|
| TRAM flap (Transverse Rectus Abdominis Muscle) | Higher chance of hernia without abdominal muscles [2]; donor site morbidity (abdominal wall weakness) | The rectus abdominis muscle is harvested, leaving the abdominal wall weakened → risk of incisional hernia |
| LD flap (Latissimus Dorsi) | Donor site seroma; shoulder weakness | Loss of latissimus dorsi function (usually well-compensated by other muscles) |
| DIEP flap (Deep Inferior Epigastric Perforator) | Complications rate is higher since the vessels are much smaller [2]; risk of flap failure from microvascular thrombosis | The perforator vessels are tiny → technically demanding microsurgery → higher flap loss rate. But it spares the muscle from graft harvest [2], preserving abdominal wall integrity |
Prosthetic devices (implants) [3]:
| Complication | Mechanism | Notes |
|---|---|---|
| Mechanical complications: migration, malposition, exposure, rupture [3] | Implant shifts, the pocket fails, or the shell degrades over time. Majority of ruptures are often silent [3] | Present with changes in breast shape/volume, capsular contracture, palpable lumps (breast or axilla), and pain [3] |
| Implant infections [3] | Bacterial contamination during surgery or haematogenous seeding | Managed by antibiotics ± explantation and irrigation of the pocket → closure over closed suction drainage [3] |
| Capsular contracture [3] | Especially post-infection or radiation [3]. The body forms a fibrous capsule around any implant (foreign body reaction); if this capsule contracts excessively → painful, fibrous capsule around implant → palpable distortion of breast [3] | The Baker classification grades capsular contracture I–IV. Grade III–IV require surgical revision (capsulotomy or capsulectomy) |
| Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) [3] | ALK-negative, CD30-positive lymphoma arising from the capsule around textured implants. The chronic inflammatory stimulus of the textured surface is thought to drive T-cell transformation | Disease confined to the capsule: capsulectomy alone is curative. Adjuvant therapies: chemotherapy (cyclophosphamide, doxorubicin, vincristine, prednisone) or anti-CD30 (brentuximab vedotin) [3] |
BIA-ALCL — Rare But Must-Know
Breast implant-associated anaplastic large cell lymphoma is a rare T-cell lymphoma associated with textured breast implants. It typically presents as a late-onset seroma around the implant (months to years after insertion). If confined to the capsule, complete capsulectomy is curative. It is ALK-negative and CD30-positive — this distinguishes it from systemic ALCL and makes it amenable to anti-CD30 targeted therapy (brentuximab vedotin).
When BCS is performed for cancer causing nipple discharge/inversion, adjuvant RT is compulsory. Complications include:
| Complication | Mechanism | Timing |
|---|---|---|
| Acute skin reactions (erythema, desquamation) | Radiation damages rapidly dividing basal keratinocytes → inflammation → skin breakdown | During and immediately after RT |
| Chronic skin changes (fibrosis, telangiectasia) | Radiation damages dermal fibroblasts and small vessels → progressive fibrosis and vascular damage | Months to years |
| Breast oedema and pain | Lymphatic damage → impaired drainage; fibrosis of breast tissue | Months |
| Rib fractures | Radiation-induced bone weakening of underlying ribs | Years |
| Radiation pneumonitis | Inflammation of underlying lung parenchyma within the radiation field | 1–6 months post-RT |
| Cardiac toxicity (especially left-sided breast RT) | Radiation to the left chest → exposure of the heart (particularly the LAD artery) → accelerated atherosclerosis, pericarditis | Years to decades |
| Secondary malignancy (angiosarcoma of irradiated breast) | Radiation-induced DNA damage in surviving cells → malignant transformation | 5–10+ years |
| Drug | Complication | Mechanism |
|---|---|---|
| Bromocriptine | Nausea, vomiting, postural hypotension, headache | Dopamine agonism in the chemoreceptor trigger zone (nausea) and peripheral vasculature (hypotension) |
| Cabergoline | Nausea, headache; rarely cardiac valvulopathy (at high doses used in Parkinson's) | 5-HT2B receptor agonism on heart valves — at the low doses used for prolactinoma, this risk is minimal but should be monitored |
| Both | Impulse control disorders (rare) | Dopamine agonism in mesolimbic pathways |
| Category | Key Complications |
|---|---|
| Missed pathological discharge | Progression of DCIS → invasive carcinoma; missed cancer |
| Duct ectasia | Periductal mastitis, breast abscess, nipple retraction |
| Lactational mastitis | Breast abscess (25%), sepsis, premature cessation of breastfeeding |
| Periductal mastitis | Subareolar abscess, periareolar fistula, recurrence, nipple retraction |
| IGM | Chronic sinuses, poor wound healing post-surgery, steroid rebound, misdiagnosis as cancer |
| Microdochectomy / major duct excision | Infection, haematoma, nipple necrosis, altered sensation, loss of breastfeeding ability, iatrogenic nipple inversion |
| Mastectomy | Seroma, skin flap necrosis, post-mastectomy pain, phantom breast, arm morbidity, frozen shoulder |
| ALND | Lymphoedema (10–20%), nerve injuries (4 nerves), seroma, Stewart-Treves syndrome |
| Breast reconstruction | TRAM: hernia; DIEP: flap failure; Implants: rupture, capsular contracture, BIA-ALCL |
| Radiotherapy | Skin reactions, fibrosis, pneumonitis, cardiac toxicity, secondary malignancy |
| Dopamine agonists | Nausea, postural hypotension, rarely cardiac valvulopathy |
High Yield Summary — Complications
-
The most important complication of nipple discharge is missed malignancy — DCIS progresses to invasive carcinoma at ~1%/year. This is why all pathological discharge mandates triple assessment.
-
Duct ectasia complications: periductal mastitis → abscess → nipple retraction. It is a benign cascade but can mimic malignancy.
-
Lactational mastitis progresses to abscess in 25% of cases. Abscess is often NOT fluctuant. Do NOT stop breastfeeding.
-
Periareolar fistula is the hallmark chronic complication of periductal mastitis — a communication between a subareolar duct and the skin. Requires fistulectomy ± total duct excision.
-
IGM: do NOT operate — slow wound healing. Steroid tapering causes rebound inflammation.
-
Mastectomy complications: seroma (most common), skin flap necrosis, post-mastectomy pain syndrome, phantom breast syndrome, arm morbidity.
-
Four nerves at risk in ALND: long thoracic (winged scapula), thoracodorsal (weak shoulder adduction/IR), medial pectoral (pec major weakness), intercostobrachial (paraesthesia of axilla/medial arm).
-
Lymphoedema after ALND occurs in up to 10–20% of patients. Late complication: Stewart-Treves syndrome (lymphangiosarcoma).
-
BIA-ALCL: ALK-negative, CD30-positive T-cell lymphoma associated with textured implants. Capsulectomy is curative if confined to capsule.
-
Capsular contracture: most common implant complication long-term, especially post-infection or post-radiation.
Active Recall - Complications of Nipple Discharge and Inversion
References
[1] Lecture slides: GC 181. Breast mass breast cancer; benign breast diseases; mammography; breast cancer screening.pdf (p40 — Axillary dissection complications) [2] Senior notes: felixlai.md (Nipple discharge and inversion pp.269–271; Duct ectasia p.280; Lactational mastitis pp.280–281; Periductal mastitis pp.281–282; IGM pp.282–283; Complications of mastectomy pp.302–303; Breast reconstruction pp.303–304; ALND complications pp.307–308) [3] Senior notes: maxim.md (Mastectomy complications p.184; ALND complications and 4 nerves p.186; Breast reconstruction and implant complications pp.187–188; BIA-ALCL p.188) [4] Senior notes: maxim.md (Section 8.5: Inflammatory breast conditions — duct ectasia complications, mastitis complications p.185)
High Yield Summary
-
Nipple discharge is classified as physiological (lactation, galactorrhoea) or pathological (serous, bloody, purulent). Pathological discharge is spontaneous, unilateral, single-duct, and serous/bloody.
-
Intraductal papilloma is the most common cause of pathological (especially bloody) nipple discharge. The bloody/serous discharge results from compromised venous/lymphatic drainage in the papilloma's peduncle.
-
Malignancy (DCIS > IDC) accounts for 5–15% of pathological nipple discharge. DCIS is the most common malignancy associated.
-
Galactorrhoea = milky, bilateral, multi-duct. Think hyperprolactinaemia — prolactinoma, drugs (antipsychotics/antiemetics), hypothyroidism, CKD.
-
Duct ectasia = older women, cheesy multi-coloured discharge, nipple inversion, NOT increased cancer risk.
-
Paget's disease = unilateral nipple eczema + underlying breast cancer (HER2+ in ~80%). Paget cells in nipple epidermis. Biopsy is mandatory. Do NOT treat as dermatitis without histology.
-
Nipple inversion: Congenital (bilateral, benign, manually evertible) vs Acquired (unilateral, progressive, must exclude malignancy). Acquired causes: carcinoma, duct ectasia, periductal mastitis, abscess/fistula, TB, IGM.
-
5Ds of nipple changes: Deviation, Discolouration, Dermatitis, Depression (retraction/inversion), Discharge.
-
History essentials for nipple discharge: unilateral/bilateral, colour, spontaneous/expressed, single/multiple duct, associated mass/lymphadenopathy, pregnancy/lactation, medications, cancer risk factors.
-
All pathological nipple discharge requires triple assessment (clinical + radiological + pathological).
High Yield Summary — Differential Diagnosis
-
Intraductal papilloma is the most common cause of pathological nipple discharge (especially bloody/serous, single-duct, unilateral).
-
DCIS is the most common malignancy associated with nipple discharge (5–15% of pathological discharge).
-
Duct ectasia = older women, cheesy multi-coloured discharge, nipple inversion, NO increased cancer risk.
-
Paget's disease = unilateral nipple eczema starting at the nipple (not areola), 97% has underlying breast CA, diagnosed by incisional biopsy showing Paget cells. Do NOT treat as dermatitis.
-
Galactorrhoea = milky, bilateral, multi-duct → check prolactin, TFTs, drug history, renal function.
-
Key discriminators: milky vs non-milky → unilateral vs bilateral → single vs multiple duct → spontaneous vs expressed → colour.
-
Acquired unilateral nipple inversion = carcinoma until proven otherwise. Always perform triple assessment.
-
Periductal mastitis = young smoker, purulent discharge, subareolar abscess, periareolar fistula. Distinct from duct ectasia (older, non-inflammatory).
-
Risk stratification: duct ectasia and periductal mastitis carry NO increased cancer risk; papilloma carries slightly increased risk (1.5–2×); ADH/ALH carries 5× risk.
High Yield Summary — Diagnosis
-
Triple Assessment (Clinical + Radiological + Pathological) = sensitivity 99.6%, specificity 93% [1][8]. Positive if ANY one component is positive. Negative only when ALL three are negative.
-
Pathological discharge criteria: spontaneous, unilateral, single-duct, serous or bloody → mandates full triple assessment.
-
Mammogram for age ≥ 35; USG for all patients; USG first-line for age < 35 or pregnant/lactating [2][3].
-
BI-RADS ≥ 4 → core needle biopsy is mandatory [3]. BI-RADS 3 → short-interval follow-up.
-
Core biopsy > FNAC because it provides architectural assessment, grading, and receptor status (ER/PR/HER2). FNAC cannot distinguish in-situ from invasive cancer.
-
If ADH/ALH on core biopsy → excisional biopsy is MANDATORY to exclude adjacent malignancy (upgrade rate 15–30%) [3][6].
-
Ductography/ductoscopy help localise intraductal lesions when imaging is inconclusive but discharge is persistent.
-
Paget's disease diagnosis: full-thickness wedge biopsy of nipple showing Paget cells. Mammography is mandatory to find the underlying cancer.
-
Galactorrhoea workup: serum prolactin → TFTs → renal function → drug history → pituitary MRI if prolactin elevated.
-
Acquired unilateral nipple inversion → triple assessment to exclude malignancy, regardless of whether discharge is present.
High Yield Summary — Management
-
Microdochectomy (excision of the diseased duct, guided by ductogram/ductoscopy) [1] is the standard surgical treatment for pathological single-duct discharge (papilloma). Major duct excision is for multi-duct or recurrent discharge.
-
Galactorrhoea: treat the cause — dopamine agonists for prolactinoma (bromocriptine/cabergoline); stop offending drugs; levothyroxine for hypothyroidism. Transsphenoidal surgery if refractory or giant adenoma + pregnancy desired.
-
Duct ectasia: conservative first — often resolves spontaneously. Microdochectomy only if persistent.
-
Lactational mastitis: antibiotics (cephalexin/dicloxacillin) + continue breastfeeding + complete emptying. Abscess → USG aspiration or I&D.
-
Periductal mastitis: Augmentin or dicloxacillin + metronidazole. Abscess → drainage. Fistula → fistulectomy ± total duct excision. Smoking cessation is critical.
-
IGM: do NOT operate — slow wound healing. NSAIDs first, antibiotics if Corynebacterium, steroids ± MTX if refractory.
-
Paget's disease: excise underlying cancer + NAC. Nipple-sparing mastectomy is contraindicated.
-
DCIS: WLE with margins ≥ 2 mm ± RT (Van Nuys score) or mastectomy. SLNB if planned mastectomy. Tamoxifen if ER+. No chemotherapy.
-
Invasive carcinoma: BCS + compulsory RT or mastectomy; axillary management by SLNB/ALND; adjuvant systemic therapy by IHC subtype (St Gallen's).
-
Contraindications to BCS: multicentric disease, high tumour:breast ratio, persistent positive margins, diffuse malignant calcifications, inflammatory breast cancer.
High Yield Summary — Complications
-
The most important complication of nipple discharge is missed malignancy — DCIS progresses to invasive carcinoma at ~1%/year. This is why all pathological discharge mandates triple assessment.
-
Duct ectasia complications: periductal mastitis → abscess → nipple retraction. It is a benign cascade but can mimic malignancy.
-
Lactational mastitis progresses to abscess in 25% of cases. Abscess is often NOT fluctuant. Do NOT stop breastfeeding.
-
Periareolar fistula is the hallmark chronic complication of periductal mastitis — a communication between a subareolar duct and the skin. Requires fistulectomy ± total duct excision.
-
IGM: do NOT operate — slow wound healing. Steroid tapering causes rebound inflammation.
-
Mastectomy complications: seroma (most common), skin flap necrosis, post-mastectomy pain syndrome, phantom breast syndrome, arm morbidity.
-
Four nerves at risk in ALND: long thoracic (winged scapula), thoracodorsal (weak shoulder adduction/IR), medial pectoral (pec major weakness), intercostobrachial (paraesthesia of axilla/medial arm).
-
Lymphoedema after ALND occurs in up to 10–20% of patients. Late complication: Stewart-Treves syndrome (lymphangiosarcoma).
-
BIA-ALCL: ALK-negative, CD30-positive T-cell lymphoma associated with textured implants. Capsulectomy is curative if confined to capsule.
-
Capsular contracture: most common implant complication long-term, especially post-infection or post-radiation.
Breast Cancer
Breast cancer is a malignant neoplasm arising from the epithelial cells of the breast ducts or lobules, with the potential for local invasion and distant metastasis.
Primary Hyperaldosteronism (conn's)
Primary hyperaldosteronism is excessive aldosterone production by the adrenal cortex, most commonly due to an adrenal adenoma or bilateral adrenal hyperplasia, resulting in hypertension, hypokalemia, and metabolic alkalosis.