Gynaecomastia

Definition: benign proliferation of glandular breast tissue in a male, caused by an increased ratio of oestrogen to androgen action on the breast. Must be distinguished from lipomastia (pseudogynaecomastia), which is fat alone with no palpable disc.

Clinical picture: a concentric, rubbery, mobile subareolar disc, often tender during the active proliferative phase, usually bilateral but frequently asymmetrical.

Why it is common in old age: testosterone falls while SHBG rises (so free testosterone falls faster), and increasing adiposity raises peripheral aromatisation of androgens to oestradiol — shifting the oestrogen:androgen ratio.

Physiological / idiopathic: senescent gynaecomastia and obesity account for a large share of cases.

Pathological causes — reduced androgen: primary or secondary hypogonadism (including Klinefelter's presenting late), chronic kidney disease, chronic liver disease, testicular atrophy.

Pathological causes — increased oestrogen: cirrhosis (reduced oestrogen clearance and raised SHBG), thyrotoxicosis, adrenal tumours, testicular Leydig or Sertoli cell tumours, and hCG-secreting tumours (bronchogenic carcinoma, germ cell tumours). Also refeeding after starvation.

Drug-induced (about a quarter of cases — the dominant cause in geriatric practice): spironolactone, digoxin, cimetidine/ranitidine, ketoconazole, calcium channel blockers, ACE inhibitors, antiandrogens and GnRH agonists used for prostate cancer, antipsychotics, metoclopramide, antiretrovirals, alcohol, cannabis, opioids — and exogenous testosterone itself, through aromatisation to estradiol.

Red flags for male breast carcinoma: a hard, eccentric (not subareolar), fixed, unilateral mass, skin dimpling, nipple retraction or bloody discharge, or axillary lymphadenopathy → mammography with core biopsy (triple assessment). Male breast cancer incidence rises with age, so an older man with an eccentric hard lump must never simply be reassured.

Investigations: a meticulous drug history and examination of testes, liver, thyroid and chest; then liver and renal function, TSH, early-morning total testosterone, LH, estradiol, beta-hCG, prolactin and DHEAS. Testicular ultrasound if a testicular mass is palpable or hCG is raised.

Management: Treat the cause — stop or substitute the offending drug, treat hypogonadism, thyrotoxicosis, liver or renal disease, and reduce weight. This alone resolves most cases. Drug therapy works only in the early, painful, proliferative phase (<12 months): tamoxifen 10–20 mg/day is the best-supported option (off-label); aromatase inhibitors are less effective. After about a year, fibrosis is established and drugs rarely help. Surgery — subcutaneous mastectomy with or without liposuction — for persistent, fibrotic or cosmetically distressing disease. Prophylaxis: tamoxifen or low-dose breast irradiation before starting antiandrogen therapy for prostate cancer. Testosterone-induced gynaecomastia in the first months of replacement is usually transient and resolves as testosterone antagonises estradiol at the breast; occasionally an oestrogen receptor antagonist or aromatase inhibitor is used briefly. Latest Updates & Current Practice (2023–Present) — 3 Points TRAVERSE (Lincoff et al., NEJM 2023; 5246 men aged 45–80) recorded gynaecomastia among the adverse events of transdermal testosterone but found no excess of prostate cancer or prostate-related events, and non-inferiority for major adverse cardiac events — reassuring for men who develop breast tenderness on testosterone therapy. Iatrogenic gynaecomastia now dominates geriatric practice — with widespread use of spironolactone in heart failure (and now of mineralocorticoid receptor antagonists generally) and of androgen-deprivation therapy for prostate cancer, the medication list should be reviewed before any endocrine work-up. Prophylaxis before androgen deprivation is now standard in men expected to receive prolonged antiandrogen monotherapy — a single fraction of breast irradiation or tamoxifen substantially reduces the incidence and pain of gynaecomastia, and is far more effective given before rather than after the breast tissue has become fibrotic.