Gynecomastia: Differential Diagnosis of Male Breast Enlargement

Gynecomastia is defined as a benign glandular enlargement of the male breast. Gynecomastia must be distinguished from breast enlargement due to tumor or fat deposition.

Differential Diagnosis of Gynecomastia

Physiological Gynecomastia

Newborn gynecomastia
Gynecomastia in adolescents

Increase in Estrogens or Androgens Causes Gynecomastia

Puberty
Obesity
Testicular tumors (Leydig cell tumor, choriocarcinoma)
Liver cirrhosis
Hyperthyroidism
Abuse of anabolic steroids

Hypergonadotropic Hypogonadism may cause Gynecomastia

Klinefelter's syndrome
Anti-androgenic therapy
Reifenstein's syndrome
Testicular feminization
Bilateral testicular disease or loss of testes (e.g. mumps orchitis)

Hyperprolactinemia causes Gynecomastia

Pituitary adenomas
Drugs (see below)

Drugs causing Gynecomastia

Antiandrogens: bicalutamide, flutamide, cyproterone acetate
Spironolactone
Metoclopramide
Cimetidine
Digitalis
Psychotropic drugs, cannabis

Idiopathic Gynecomastia

The cause of gynecomastia cannot be identified in 50%. Gynecomastia is associated with the following chronic diseases: liver cirrhosis, diabetes mellitus, tuberculosis, heart failure and renal insufficiency.

Non-glandular Male Breast Enlargement

Obesity: combination of excessive caloric intake and lack of physical activity. Alcohol consumption increases the caloric intake.
Tumors are rare and often one-sided: breast cancer, fibroadenoma, neurofibroma.