Medical history and physical examination are the most important components of the evaluation of a patient with gynecomastia. A detailed history should focus on time of onset and duration of the gynecomastia, associated symptoms (e.g., mastalgia, bleeding or nipple discharge), presence of systemic disease (especially liver, kidney, adrenal, thyroid, pituitary glands, testes, and prostate), history of recent weight change, presence of risk factors for breast cancer17 (e.g., BRCA2 carriers), and use of medications and recreational drugs (e.g., nonprescription medications, anabolic steroids, dietary supplements, marijuana).
Physical examination should include pubertal development stage, including assessment of voice changes, height increase, testes size, facial and body hair development, penile size and development, and muscle mass increase, and presence of any testicular masses. The breasts should carefully be inspected and palpated for the presence of unusual firmness, asymmetry, nipple discharge, axillary lymphadenopathy, and also to differentiate true gynecomastia from pseudogynecomastia. The normal male breast is relatively flat with a certain degree of fullness around the nipple–areola complex (NAC).18,19 This may vary depending on the degree of chest muscle hypertrophy often seen in athletes and body builders. On average, the nipple is located at 20 cm from the sternal notch in males, and the NAC measures 28 mm.
Following a comprehensive medical history and physical examination findings of age-appropriate physical and sexual development, no further investigation is warranted. Observation and reassurance should be the mainstays of treatment. If gynecomastia is present in prepubertal-aged boys, further investigation should be undertaken to search for endocrinopathy. In male adolescents with gynecomastia, if the physical examination provides signs suggestive of an underlying disorder, diagnostic blood tests to assess serum levels of luteinizing hormone, follicle-stimulating hormone, testosterone, estradiol, prolactin, dehydroepiandrosterone, and human chorionic gonadotropin may be useful.2,3