AKT · Endocrine/Breast

Gynaecomastia

Benign glandular breast enlargement in males (oestrogen:androgen imbalance — physiological, drugs, disease)

Overview

Benign proliferation of male glandular breast tissue from a relative excess of oestrogen over androgen. Physiological (neonatal, puberty, older age), drug-induced (spironolactone, digoxin, antipsychotics, anti-androgens, cannabis), or from disease (liver cirrhosis, hypogonadism, hyperthyroidism, oestrogen-secreting or hCG-secreting tumours). A soft, symmetrical, mobile subareolar disc — the task is to find the cause and exclude male breast cancer and hormone-secreting tumours.

Recognise

Soft, mobile, often tender, SYMMETRICAL subareolar glandular tissue (concentric disc beneath the nipple), frequently bilateral
Pubertal (common, self-limiting) or older men; drug history; signs of the underlying cause (chronic liver disease, hypogonadism, thyrotoxicosis)
Distinguish from pseudogynaecomastia (fat) and from cancer (hard, fixed, eccentric)

Red flags

Hard, fixed, eccentric, rapidly growing mass with nipple change → male breast CANCER (refer)
hCG-secreting tumour (testicular/lung) or oestrogen-secreting tumour → examine the testes, investigate

Differentials & how to tell them apart

Pseudogynaecomastiafatty enlargement without a firm glandular disc (obesity)

Male breast cancerhard, fixed, eccentric, unilateral, nipple change — not a soft symmetrical disc

Drug-inducedspironolactone, digoxin, antipsychotics, anti-androgens, cannabis, finasteride — the commonest reversible cause

Gynaecomastia — symmetrical subareolar glandular enlargement
ProloSozz / CC BY-SA 4.0 — Wikimedia Commons

Investigations

History (drugs) and examination (testes, liver, thyroid). Bloods: LFTs, U&Es, TFTs, testosterone/LH/FSH, oestradiol, hCG, prolactin. Imaging/biopsy if features suggest cancer; testicular ultrasound if hCG/mass.

Management

Identify and treat the cause (stop the drug); reassure physiological cases

1Examine for the cause (drugs, testes, liver, thyroid) and check the relevant bloods. Reassure physiological/pubertal cases; stop or switch a causative drug.Gate: Exclude male breast CANCER (hard, fixed, eccentric mass + nipple change) and a hormone-secreting TUMOUR (examine the testes; check hCG/oestradiol) before labelling it benign gynaecomastia — this is the classic reverseCause chain (a sign pointing back to a drug or a tumour)
2Persistent/distressing → tamoxifen or surgery; treat the underlying disease (cirrhosis, hypogonadism, thyrotoxicosis).

Stop/switch the causative drug; treat the cause — often reversible (e.g. spironolactone, digoxin)

Reassurance (pubertal/physiological) — usually resolves spontaneously

Tamoxifen / surgery — for persistent, troublesome or cosmetically significant cases (specialist)

Key points

Soft, symmetrical, mobile subareolar disc = gynaecomastia → find the cause (drug, liver, hypogonadism, hCG/oestrogen tumour). The exam loves the reverse chain: gynaecomastia → which DRUG (spironolactone/digoxin) or which TUMOUR (hCG-secreting). Hard/fixed/eccentric = cancer instead.

Monitor & prognosis

Resolution after removing the cause; recheck for tumour if unexplained.

Usually benign/reversible.

Source: Society for Endocrinology; BNF (drug causes)