gynecomastia /gī′nəkōmas″tē·ə, jī′-, jin′-/ [Gk, gyne + mastos, breast] , an abnormal enlargement of one or both breasts in males. Milk production may or may not be present. The condition is usually temporary and benign. It may be caused by hormonal imbalance; a tumor of an adrenal gland, testis, or pituitary; use of medication that contains estrogens or steroidal compounds; or failure of the liver to inactivate circulating estrogen, as in alcoholic cirrhosis. Less commonly the gynecomastia may be caused by a hormone-secreting tumor of the breast, lung, or other organ. It tends to subside spontaneously but, if marked, may be corrected surgically for cosmetic or psychological reasons. Biopsy may be performed to rule out cancer. Also called gynecomasty. Also spelled gynaecomastia.
