Breast lump

A breast lump is a discrete mass or thickening felt by the patient or the clinician. Most breast lumps are benign, but breast cancer is the commonest cancer in women in most countries, and no clinical features rule it out. Every new discrete lump needs triple assessment: clinical examination, imaging and tissue sampling.

Epidemiology. Fibroadenoma is the commonest lump under 30 years. Cysts and fibrocystic change dominate between 35 and 50 years. Cancer risk rises steeply from age 40, and in many African and Asian settings cancer presents earlier and at a later stage. Breast cancer in men accounts for under 1% of cases, and gynaecomastia is the commonest cause of a lump in men.

Classification.

• Benign: fibroadenoma, cyst, fibrocystic change, intraductal papilloma, fat necrosis, lipoma, hamartoma.
• Inflammatory and infective: lactational and non-lactational abscess, periductal mastitis, granulomatous mastitis, tuberculous mastitis.
• Malignant: ductal carcinoma in situ, invasive carcinoma of no special type, invasive lobular carcinoma, special types, Paget disease, inflammatory breast cancer, malignant phyllodes tumour, sarcoma, lymphoma, metastasis.
• Borderline and uncertain: phyllodes tumour, atypical hyperplasia, radial scar, papillary lesions.

Triple assessment grading. Clinical (P1 to P5), imaging (M or U 1 to 5, or BI-RADS 0 to 6) and pathology (B1 to B5, with B3 uncertain malignant potential, B4 suspicious and B5 malignant). Imaging BI-RADS categories: 0 incomplete, 1 negative, 2 benign, 3 probably benign (malignancy risk 2% or less), 4 suspicious (4A 2 to 10%, 4B 10 to 50%, 4C 50 to 95%), 5 highly suggestive (95% or more), 6 known cancer.

Key distinctions. A hard, irregular, painless, fixed lump with skin tethering is cancer until proved otherwise, though cancers can be smooth and tender. A fibroadenoma is smooth, firm, mobile and non-tender. Cysts fluctuate with the cycle. Rapid growth suggests phyllodes tumour or cancer. In a lactating woman, a lump may be a galactocele, abscess or pregnancy-associated cancer. An inflammatory breast with no response to antibiotics needs biopsy to exclude inflammatory breast cancer.

History.

• Lump: duration, change in size, cyclical variation, pain, trauma, nipple discharge (bloody or single duct versus bilateral and milky), skin or nipple change, associated fever.
• Risk factors: age, early menarche or late menopause, nulliparity or late first pregnancy, breastfeeding history, hormone replacement therapy or combined contraception, obesity, alcohol, previous breast biopsy with atypia, previous chest radiotherapy before age 30, family history (first degree relatives, age at diagnosis, bilateral disease, ovarian, male or pancreatic cancer, known BRCA1, BRCA2, PALB2 or TP53 variants).
• Systemic features: bone pain, cough, breathlessness, jaundice, headache, weight loss.
• HIV status and previous tuberculosis in endemic settings.

Examination.

• Inspect both breasts sitting with arms by the side, raised and hands on hips: asymmetry, dimpling, peau d'orange, erythema, nipple inversion or eczema, ulceration, venous pattern.
• Palpate all quadrants with the flat of the fingers, with the patient sitting and supine, including the retroareolar region and axillary tail.
• Describe the lump by site (clock face and distance from the nipple), size in two dimensions, shape, surface, edge, consistency, mobility on the chest wall, fixity to skin or muscle (tested with the hands on hips), tenderness and overlying skin.
• Nipple: discharge (colour, single or multiple ducts), retraction, eczema.
• Axillary nodes (all levels), supraclavicular and cervical nodes, liver, spine tenderness, chest signs.
• Record findings on a diagram. In men, examine for a concentric subareolar swelling (gynaecomastia) or an eccentric, hard lump.

Red flags.

• Discrete, hard, irregular or fixed lump, or any lump that persists over a menstrual cycle in a woman over 30.
• Skin tethering, peau d'orange, new nipple retraction, bloody nipple discharge, nipple eczema that does not clear in 2 weeks, axillary or supraclavicular nodes.
• Rapidly growing lump, lump in a man, or a lump with known genetic risk.
• Erythema, swelling and tenderness not responding to 1 to 2 weeks of antibiotics (inflammatory breast cancer).
• Bone pain, breathlessness, jaundice or neurological symptoms.

Special groups.

• Pregnancy and lactation: examine and image as usual, and biopsy is safe.
• Adolescents and young women: ultrasound first, and cancer is rare.
• Older women and those with high risk: lower threshold for imaging and biopsy.
• Men: gynaecomastia drugs (spironolactone, cimetidine, anabolic steroids, antiretrovirals, digoxin), liver disease, hypogonadism and tumours.
• Women with implants, gender diverse people on hormone therapy, and carriers of high risk variants: specialist imaging.

Benign solid lesions. Fibroadenoma (including giant and juvenile types), phyllodes tumour (benign, borderline or malignant), intraductal papilloma, hamartoma, lipoma, fat necrosis, radial scar, sclerosing adenosis, pseudoangiomatous stromal hyperplasia, diabetic mastopathy, silicone granuloma.

Cystic and fibrocystic. Simple cyst, complex cyst, fibrocystic change, galactocele, duct ectasia.

Inflammatory and infective. Lactational mastitis and abscess, non-lactational (periductal) mastitis and abscess, granulomatous lobular mastitis, tuberculous mastitis, sebaceous cyst, superficial thrombophlebitis (Mondor disease), haematoma.

Malignant.

• Invasive carcinoma of no special type (ductal), invasive lobular carcinoma, ductal carcinoma in situ.
• Mucinous, tubular, papillary, medullary and metaplastic cancers, Paget disease of the nipple, inflammatory breast cancer.
• Malignant phyllodes tumour, angiosarcoma, primary breast lymphoma, metastases to the breast (melanoma, lung, ovarian, lymphoma).
• Male breast cancer.

Non-breast lumps. Axillary tail breast tissue, accessory breast tissue, enlarged axillary node, chest wall lipoma, costochondritis (Tietze syndrome), rib tumour, and pectoral muscle lesion.

Male. Gynaecomastia (physiological, drug induced, hormonal, cirrhosis), lipomastia, male breast cancer.

Principle. Triple assessment in all patients with a discrete lump or high suspicion, ideally at one visit in a breast clinic, with results reviewed by a multidisciplinary team.

Imaging.

• Under 30 years: ultrasound first. Mammography is added if ultrasound or clinical suspicion for cancer is high.
• 30 to 39 years: ultrasound, with mammography when suspicious or for microcalcification.
• 40 years and over: mammography (tomosynthesis where available) with ultrasound for any lump.
• Breast MRI for high risk carriers, suspected invasive lobular cancer, discordant findings, dense breasts when other imaging is inconclusive, implant assessment, Paget disease with negative imaging, and extent assessment before surgery in selected patients.
• Ultrasound features that favour malignancy: irregular or spiculated margin, taller than wide shape, hypoechoic texture, posterior shadowing, non-parallel orientation, calcifications. Simple cysts are anechoic with posterior enhancement.
• Axillary ultrasound with biopsy of any abnormal node.

Tissue sampling.

• Core needle biopsy (14 gauge, three or more cores, ultrasound or stereotactic direction) is preferred for solid lesions because it gives histology, grade and receptor status. Vacuum assisted biopsy for microcalcifications and small lesions.
• Fine needle aspiration for cysts and nodes (cytology cannot separate in situ from invasive cancer). Clip placement in the lesion before neoadjuvant therapy.
• For confirmed cancer: oestrogen receptor, progesterone receptor, HER2 status and Ki-67, with grade.
• Skin punch biopsy for suspected inflammatory breast cancer, and nipple biopsy for suspected Paget disease. Culture of aspirated pus, and acid fast bacilli smear and culture and tissue histology for chronic or granulomatous disease.

Staging (stage III disease, symptoms, or large or aggressive tumours). CT chest, abdomen and pelvis plus bone scan (or whole body PET-CT), full blood count, urea, creatinine, liver tests, alkaline phosphatase and corrected calcium. Genetic counselling and testing for patients meeting risk criteria (young age, triple negative disease, bilateral disease, strong family history, male breast cancer).

Interpretation.

• Benign imaging with benign (B2) pathology and a clinically benign lump is concordant, and the lump can be observed or excised.
• Discordance (suspicious clinical or imaging findings with benign pathology) needs repeat biopsy or excision.
• B3 lesions (atypical hyperplasia, papilloma with atypia, radial scar, phyllodes tumour) need multidisciplinary review and often excision.

Limitations. Mammography is less sensitive in dense breasts, especially in younger women. Ultrasound depends on the operator. Core biopsy may miss the lesion. Fine needle aspiration can give inadequate samples. Resource limited settings may only have clinical examination, ultrasound and fine needle aspiration, which still allows diagnosis when core biopsy is not available, but cannot give receptor status.

General steps.

• Urgent referral to a breast service (seen within 2 weeks) when cancer is suspected. Do not wait for imaging before referral.
• Triple assessment, then communication of results with a named contact and psychological support.
• Do not treat a lump with antibiotics unless there is a clear infective picture, and review after 1 to 2 weeks.

Simple cyst. Aspirate under ultrasound direction if symptomatic or for diagnosis, send fluid for cytology only if bloody, and reassure. Recurrent cysts (more than twice), complex cysts or residual lumps need biopsy.

Fibroadenoma.

• Confirmed fibroadenoma (concordant triple assessment) in a woman under 40 years and under 3 cm: reassure and offer observation with ultrasound at 6 and 12 months. Most stay stable or shrink.
• Excision (or vacuum excision) for size over 3 cm, rapid growth, patient preference, discordant results, B3 features, or phyllodes tumour not excluded.
• Phyllodes tumour: wide local excision with a margin of 1 cm or more. Axillary surgery is not needed. Malignant phyllodes tumour needs oncology review.

Fat necrosis and fibrocystic change. Reassure after concordant assessment. Treat pain with simple analgesia and a supportive bra.

Breast abscess and mastitis.

• Continue breastfeeding or expression from the affected breast, with frequent feeding and analgesia.
• Flucloxacillin 500 mg orally every 6 hours (up to 1 g every 6 hours in severe infection) for 7 to 10 days; maximum 4 g daily; take on an empty stomach; monitor liver tests (cholestatic jaundice can occur weeks after use), and reduce the dose in severe kidney impairment. Penicillin allergy: clindamycin 300 to 450 mg orally every 6 hours for 7 to 10 days; maximum 1.8 g daily; monitor for Clostridioides difficile infection. Non-lactational or periductal abscess: amoxicillin with clavulanic acid 500/125 mg orally every 8 hours for 7 days (reduce to every 12 hours for eGFR 10 to 30 mL/min). Where MRSA is common, use local data, and avoid doxycycline in breastfeeding. These drugs are compatible with breastfeeding.
• Paracetamol 1 g orally every 6 hours (maximum 4 g daily; 3 g daily if weight under 50 kg, malnutrition, alcohol excess or liver disease) and ibuprofen 400 mg orally every 8 hours with food for short courses (maximum 1.2 g daily without medical direction, 2.4 g daily under supervision; avoid in asthma sensitive to aspirin, peptic ulcer, kidney disease and heart failure).
• Abscess (fluctuant lump on ultrasound): ultrasound directed needle aspiration under local anaesthesia, repeated every 1 to 3 days, or small incision and drainage for large, loculated or necrotic skin abscesses. Send pus for culture.
• Non-lactational abscess or recurrent disease: biopsy of the wall to exclude cancer, and treatment of smoking and underlying duct disease.
• Granulomatous mastitis: biopsy with culture, exclude tuberculosis, and specialist treatment (observation, corticosteroids or methotrexate).
• Tuberculous mastitis: antituberculous therapy with isoniazid 5 mg/kg (maximum 300 mg), rifampicin 10 mg/kg (maximum 600 mg), pyrazinamide 25 mg/kg (maximum 2000 mg) and ethambutol 15 mg/kg (maximum 1600 mg) orally once daily for 2 months, then isoniazid and rifampicin for 4 months, with pyridoxine 10 to 25 mg daily; monitor liver tests, visual acuity and uric acid.
• Inflammatory breast cancer: skin biopsy, staging imaging and neoadjuvant chemotherapy by oncology.

Breast cancer (initial care).

• Multidisciplinary planning: surgery (breast conserving surgery or mastectomy, sentinel lymph node biopsy for clinically node negative disease, axillary dissection or radiotherapy for node positive disease), radiotherapy, and systemic therapy, chosen by stage, receptors and patient preference.
• Neoadjuvant systemic therapy for large, node positive, triple negative or HER2 positive tumours. HER2 targeted therapy, chemotherapy and immunotherapy are directed by oncology.
• Endocrine therapy for oestrogen receptor positive disease: tamoxifen 20 mg orally once daily for 5 to 10 years (premenopausal or postmenopausal); monitor for hot flushes, venous thromboembolism, endometrial symptoms and eye symptoms; avoid with strong CYP2D6 inhibitors (paroxetine, fluoxetine, bupropion), and in pregnancy; maximum 20 mg daily. Postmenopausal women: anastrozole 1 mg orally once daily or letrozole 2.5 mg orally once daily for 5 years or longer; monitor bone density, lipids, joint pain and vitamin D; avoid in premenopausal women unless ovarian suppression is given.
• Bone health: calcium and colecalciferol 800 to 1000 IU once daily, with bisphosphonate when indicated under specialist direction.
• Genetic counselling for eligible patients and family screening.
• Oncology emergencies (hypercalcaemia, spinal cord compression, brain metastases, pleural effusion) need acute care by the oncology team.

Pregnancy associated breast cancer. Ultrasound, mammography with abdominal shielding, and core biopsy are safe. Surgery is possible in any trimester. Chemotherapy is avoided in the first trimester and can be given from the second. Radiotherapy, endocrine therapy and HER2 therapy are deferred until after delivery.

Men. Gynaecomastia: stop the drug where possible, check liver, kidney, thyroid and testosterone, oestradiol and hCG when indicated, with ultrasound or mammography and biopsy for hard or eccentric lumps. Male breast cancer is treated like breast cancer in women, with genetic testing.

Monitoring. Fibroadenoma surveillance at 6 and 12 months with ultrasound, B3 lesions reviewed by the multidisciplinary team, and patients with benign assessment advised to return for change. Review of pathology within 1 week.

Referral and escalation. Breast surgery and breast clinic for all discrete lumps, oncology for cancer, radiology for biopsy, plastic surgery for reconstruction, genetics for hereditary risk, palliative care for advanced disease, and mental health or counselling services.

Admission criteria. Rare. Admit for sepsis from breast abscess, haemodynamic instability, hypercalcaemia, cord compression, or surgical care.

Discharge and safety netting. Patients with concordant benign assessment are told the result in person, given written information, and advised to return for lump growth, new lumps, skin or nipple change, nipple discharge, pain that changes or a new lump in the other breast. Breast awareness and age appropriate screening continue.