Gynaecomastia
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Direct answer
Gynaecomastia is benign enlargement of male breast glandular tissue, caused by an imbalance between oestrogen and androgen action at the breast. It occurs physiologically in newborns, adolescents and older men, and pathologically with drugs such as spironolactone, digoxin and cimetidine, liver disease, hypogonadism, hyperthyroidism and testicular or adrenal tumours.
What you must remember
- Glandular versus fatty: true gynaecomastia is firm, disc-like and subareolar, whereas lipomastia is soft, fatty and extends beyond the areola.
- Neonatal and pubertal: maternal oestrogen in newborns and transient pubertal oestrogen dominance usually regress without treatment, often within a couple of years.
- Drugs: spironolactone, digoxin, cimetidine, ketoconazole, finasteride and anabolic steroids are the commonest reversible causes.
- Liver disease: cirrhosis raises oestrogen effects through reduced hepatic clearance and increased peripheral conversion of androgens.
- Hyperthyroidism: raises sex hormone-binding globulin and peripheral oestrogen production, both of which promote glandular growth.
- Klinefelter syndrome: 47,XXY with hypogonadism, small firm testes and raised gonadotropins is a classic genetic cause.
- Tumour clues: a raised hCG suggests a germ cell tumour, and any unilateral testicular mass needs ultrasound.
- Management: stop the offending drug, treat the underlying cause, use tamoxifen for tender or persistent glandular disease, and consider surgery for established cases.
Working up gynaecomastia by cause
Most gynaecomastia is physiological or drug-related, so history and examination come first. Hormone tests are reserved for suspicious features such as a unilateral mass, rapid onset or signs of hypogonadism.
| Category | Examples | Key test |
|---|---|---|
| Physiological | Newborn, puberty, older men | Observation over time |
| Drugs | Spironolactone, digoxin, cimetidine, anabolic steroids | Stop the drug, then reassess |
| Hypogonadism | Klinefelter syndrome, testicular failure | LH, FSH, testosterone, karyotype |
| Endocrine or systemic | Hyperthyroidism, cirrhosis, chronic kidney disease | Thyroid, liver and renal function tests |
| Tumour | Testicular germ cell, Leydig or Sertoli cell tumour, adrenal tumour | Testicular ultrasound, hCG, oestradiol, testosterone |
A raised oestradiol with low testosterone suggests increased aromatisation or hypogonadism, while a raised hCG points to a germ cell tumour. Imaging is needed for any unilateral mass, and an adrenal source should be considered when oestrogen or androgen levels are abnormal. Testosterone and oestradiol are read together, because a high oestrogen to androgen balance drives the glandular proliferation even when absolute levels look near normal.
Where the exam tries to catch you
Examiners test the difference between true and fatty enlargement, and the order of the work-up.
- Trap: Labelling every male breast enlargement as gynaecomastia. Correct: Lipomastia is fatty, without glandular tissue, and is a common mimic in obese men.
- Trap: Ordering hormone profiles before stopping a drug. Correct: Spironolactone, digoxin and similar drugs are the commonest reversible cause, so withdrawal comes first.
- Trap: Assuming pubertal gynaecomastia always needs treatment. Correct: It is usually transient, and only persistent or painful cases after a couple of years are evaluated further.
Frequently asked questions
How does lipomastia differ from true gynaecomastia?
Lipomastia is fatty breast enlargement without glandular tissue, usually seen in obese men. True gynaecomastia is firm, disc-like and centred on the areola, and it may be tender in the early stages.
Which drugs most often cause gynaecomastia?
Spironolactone, digoxin, cimetidine, ketoconazole, finasteride and anabolic steroids are common drug causes of gynaecomastia. Stopping the drug is the first step, and the breast tissue often regresses over months after withdrawal.
When is gynaecomastia an indication for urgent evaluation?
A unilateral mass, rapid enlargement, a hard irregular nodule or signs of hypogonadism need prompt evaluation, because testicular or adrenal tumours can cause gynaecomastia. Testicular ultrasound and hormone levels, including hCG and oestradiol, form the initial work-up.
Which hormone pattern suggests Klinefelter syndrome in gynaecomastia?
Raised LH and FSH with low testosterone suggest primary hypogonadism, and a karyotype confirms Klinefelter syndrome with 47,XXY. Small firm testes are an important examination clue in these patients.