Breast Lumps
Breast lumps are extremely common, with most being benign. Triple assessment (clinical, imaging, tissue diagnosis) at a one-stop breast clinic is the standard approach for evaluation.
Key Facts
~90% of breast lumps are benign; cancer is found in ~10% of referrals to breast clinic Triple assessment: Clinical examination + imaging (mammography ≥40/US <40) + tissue diagnosis (core biopsy/FNA) Fibroadenoma: Most common benign tumour; firm, smooth, mobile ('breast mouse'); peak age 20-30; may involute or rarely grow Breast cyst: Fluid-filled, smooth, may be tender; common peri-menopausally; diagnosed and treated by US-guided aspiration Fat necrosis: History of trauma/surgery; firm, irregular; can mimic carcinoma on examination and mammography — biopsy essential NICE NG12: 2WW referral for unexplained breast lump ≥30; or lump + skin/nipple changes at any age Galactocele: Milk-filled cyst in lactating/recently lactating women All solid breast lumps should be biopsied (core biopsy preferred over FNA for solid lesions — provides histological architecture)
Overview
Key Facts
Breast lumps are one of the commonest presentations to primary care and breast clinics. The systematic triple assessment approach ensures accurate diagnosis and timely detection of malignancy.
Epidemiology
Breast lumps are extremely common. ~90% of referrals to breast clinic are benign. Fibroadenoma is the most common benign tumour. Breast cysts are the most common cause of a discrete breast lump in women aged 35-50. Cancer accounts for ~10% of breast clinic referrals.
Aetiology
By age group:
- <25: Fibroadenoma most common; rarely cancer
- 25-40: Fibroadenoma, cyst; cancer less common but possible
- 40-55: Cyst, fibrocystic change, cancer becomes more common
- >55: Cancer must be excluded; cysts become less common post-menopause
Pathophysiology
- Fibroadenoma: Proliferation of both stromal and epithelial components; oestrogen-sensitive
- Breast cyst: Arise from terminal duct lobular units; apocrine metaplasia of epithelium
- Fibrocystic change: Spectrum of benign changes — cysts, fibrosis, epithelial hyperplasia, sclerosing adenosis
- Fat necrosis: Trauma → fat cell death → inflammatory reaction → fibrosis → firm lump ± calcification
Clinical Presentation
Fibroadenoma
- Firm, smooth, well-defined, mobile ('breast mouse')
- Usually 2-3cm; painless
- Peak age 20-30
- Giant fibroadenoma if >5cm
- May be multiple (~15%)
Breast Cyst
- Smooth, well-defined, fluctuant
- May be tender (especially pre-menstrually)
- Can appear suddenly
- Peri-menopausal (35-50 years)
- Simple cysts are benign; complex cysts require further assessment
Fibrocystic Change
- Cyclical breast pain and lumpiness
- Usually bilateral upper outer quadrant
- Improves after menopause
- Spectrum of histological changes
Fat Necrosis
- History of trauma or surgery
- Firm, irregular lump — can mimic carcinoma
- May have skin dimpling or retraction
- Mammography may show calcification
Red Flags (Refer 2WW)
- Hard, irregular, fixed lump
- Skin tethering, peau d'orange, nipple retraction
- Bloody nipple discharge
- Axillary lymphadenopathy
- Any breast lump in women ≥30
- Any lump with suspicious features at any age
Differential Diagnosis
| Diagnosis | Age Group | Key Features | Investigation |
|---|---|---|---|
| Fibroadenoma | 20-30 | Smooth, mobile, firm | US, core biopsy |
| Breast cyst | 35-50 | Smooth, fluctuant, tender | US, aspiration |
| Breast cancer | Any (>40 higher risk) | Hard, irregular, fixed | Triple assessment |
| Fat necrosis | Any (post-trauma) | Firm, irregular, trauma history | Mammography, core biopsy |
| Breast abscess | Lactating women | Painful, warm, erythematous | US, aspiration/I&D |
| Phyllodes tumour | 40-50 | Large, rapidly growing | US, core biopsy |
| Gynaecomastia (males) | Puberty/elderly | Bilateral disc of tissue behind nipple | Clinical, exclude drugs |
Diagnosis / Investigation
Triple Assessment
1. Clinical examination:
- Inspection: Symmetry, skin changes, nipple changes
- Palpation: Location, size, consistency, mobility, fixity, axillary nodes
2. Imaging:
- Mammography: Women ≥40 (sensitivity increases with age due to less dense tissue)
- Ultrasound: Women <40 (dense breast tissue); also for cyst assessment and biopsy guidance
- MRI breast: Selected cases (BRCA carriers, lobular cancer, implants)
3. Tissue diagnosis:
- Core biopsy (14G needle): Preferred for solid lesions — histological architecture, receptor status
- FNA: Cytology only; useful for lymph nodes, cyst aspiration
- Vacuum-assisted biopsy: For microcalcifications or small lesions
Results Classified as:
- Imaging (U/M score): U1-5 (ultrasound) / M1-5 (mammography) — 5 = malignant
- Pathology (B score): B1-5 — B5 = malignant
Management
Fibroadenoma
- <3cm, classic features, age <40: Conservative management with clinical/US follow-up
- >3cm, growing, atypical: Excision biopsy
- Vacuum-assisted excision: Alternative to surgical excision for confirmed fibroadenomas
- Observation is acceptable — many involute spontaneously
Breast Cyst
- Simple cyst: US-guided aspiration — fluid aspirated; if clear and lump resolves, no further action
- Bloodstained aspirate: Send for cytology — investigate further
- Complex cyst: Core biopsy — exclude intracystic carcinoma
- Recurrent cyst: Re-aspirate; consider excision if multiple recurrences
Fat Necrosis
- If benign on triple assessment: Reassurance and observation
- If any diagnostic uncertainty: Excision biopsy
Breast Abscess
- US-guided aspiration + antibiotics (flucloxacillin 500mg QDS)
- Incision and drainage: If aspiration fails or large abscess
- If non-lactational, exclude underlying malignancy
Referral Criteria
- 2WW criteria as per NICE NG12
- Any solid breast lump — referral to breast clinic for triple assessment
- Breast lump in male — exclude cancer
Prognosis
- Fibroadenoma: Benign; ~30% involute spontaneously; <0.3% risk of associated malignancy
- Breast cyst: Benign; slight increased risk of subsequent breast cancer (~1.5-2×)
- Fat necrosis: Benign; no malignant potential
- Phyllodes tumour: Borderline/malignant variants require wide excision; local recurrence risk ~15-25%
- Breast cancer: See Breast Cancer topic
Other Relevant Information
Breast Lump Assessment by Age
| Age | Most Common Lump | Key Action |
|---|---|---|
| <25 | Fibroadenoma | US, core biopsy if atypical |
| 25-40 | Fibroadenoma, cyst | Triple assessment |
| 40-55 | Cyst, fibrocystic change, cancer | Triple assessment (mammography + US) |
| >55 | Cancer until proven otherwise | Triple assessment, 2WW referral |
Classification Scoring
| Grade | Imaging (U/M) | Pathology (B) |
|---|---|---|
| 1 | Normal | Normal/unsatisfactory |
| 2 | Benign | Benign |
| 3 | Indeterminate/probably benign | Uncertain malignant potential |
| 4 | Suspicious of malignancy | Suspicious |
| 5 | Malignant | Malignant |