Gynecomastia means enlargement of the male breast. The definition has nothing to do with what causes the enlargement or what tissue it is composed of. It is most common around puberty and can involve one or both sides. Most commonly the enlargement is centralized in the breast but occasionally it is not. It is present to some degree in about a third of male population. The majority of cases are physiological or drug induced. Drug induced gynecomastia just requires cessation of the causative drug. If the gynecomastia is resistant to treatment or is the adolescent type but persistent surgery is required.

The type of surgery depends on the type of tissue contributing to the breast enlargement.

glandular: requires surgical removal of glandular tissue
fatty-glandular: requires surgical removal of glandular tissue with or without removal of adjacent fat to give the best overall shape
simple fatty: requires diet/exercise for weight loss, possibly removal of the fat