[Physiology and physiopathology of breast development in men].

Development of breasts in male subjects is a characteristic feature of gynecomastia, a not infrequent condition as it may be a physiological feature present at birth or developing during puberty and old age. The possibility of an underlying pathological process has always to be considered. Male breast enlargement may result from voluntary or involuntary ingestion of estrogens or medication possessing anti-androgenic activity. Pathological gynecomastia is due to either an excessive production of estrogens or a drop in the plasma T/E2 ratio, medical treatment is unsatisfactory, and mammectomy is required when esthetic considerations are of primary importance, after investigations to establish the etiology of the gynecomastia.