Gynecomastia is the enlargement of the breast tissue in males that causes the appearance of male breasts.
Gynecomastia can occur in one or both breasts and involves excess breast tissue rather than fat tissue. Typical symptoms are breast tenderness, swelling, pain and, in some instances, nipple discharge.
Gynecomastia usually results from a hormone imbalance that decreases testosterone and increases estrogen. Other triggers include certain medications, alcohol and street drugs (such as marijuana), hyperthyroidism, kidney or liver failure, and cirrhosis. The risk for gynecomastia increases with age, with at least one in four men between 50 and 80 developing the condition. While it is not a serious health problem, those with gynecomastia are often embarrassed by the appearance of developed breasts.