Gynecomastia
Gynecomastia is benign proliferation of glandular and stromal tissue in the male breast driven by an increased estrogen-to-androgen ratio; treatment removes the cause, adds tamoxifen 10-20 mg daily for painful or persistent disease, and reserves surgery for fibrotic or malignant cases, after excluding pseudogynecomastia and male breast cancer.
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What this article covers
- Overview
Definition: gynecomastia is a benign proliferation of glandular and stromal tissue in the male breast, caused by an increased ratio of estrogen to androgen action on breast tissue.
- Epidemiology
Trimodal age distribution: peaks occur in neonates (transplacental maternal estrogen), pubertal boys, and older men.
- Risk factors
Medications: spironolactone, cimetidine, ketoconazole, metronidazole, estrogens, antiandrogens, 5-alpha reductase inhibitors, and protease inhibitors are the most commonly implicated drugs.
- Pathophysiology
Core mechanism: any process that raises the effective estrogen-to-androgen ratio acting on breast tissue drives ductal epithelial proliferation and periductal stromal growth.
- Clinical features
Bilateral, soft-to-firm, mobile subareolar tissue: the hallmark finding is palpable, rubbery to firm glandular tissue concentric with and centered beneath the areola, more than 0.5 cm in diameter…
- Differential diagnosis
Male breast cancer: unilateral, firm, fixed, eccentric to the areola; nipple retraction in 40-50% of cases, overlying skin change or ulceration, bloody discharge, axillary adenopathy; strongest risk…
- Diagnosis
This is a clinical diagnosis made on physical examination: palpation of a discrete disc of subareolar glandular tissue greater than 0.5 cm in diameter, concentric with the areola, typically bilateral…
- Management
First, identify and remove or treat the underlying cause: stop or substitute any implicated drug (for example switch spironolactone to eplerenone 25 mg PO daily, titrated to a target of 50 mg PO…
- Complications
Missed or delayed diagnosis of male breast cancer: the most serious complication is mistaking a malignant mass for benign gynecomastia, since both can cause breast enlargement and, early on, tenderness.
- Prognosis
Excellent for physiologic and drug-induced gynecomastia: most pubertal and drug-induced cases regress fully within months of hormonal maturation or drug discontinuation.
- Prevention
Medication substitution before prescribing known offenders: when a mineralocorticoid receptor antagonist is required, favor eplerenone 25-50 mg PO daily over spironolactone in patients at risk for…
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