Definition

Gynecomastia is the development of prominent breast tissue in the male.

Alternative Names

Breast development in a male

Considerations

The most common cause of gynecomastia in the male is puberty. The condition may occur in one or both breasts and begins as a small lump beneath the nipple, which may be tender. The breasts often enlarge unevenly. Gynecomastia during puberty is not uncommon, is self-limiting, and usually goes away over a period of months.

In newborns, breast development may be associated with milk flow (galactorrhea). This condition usually lasts for a couple of weeks and in rare cases may persist until the child is two years old. It is caused by exposure to maternal hormones.

Other causes of gynecomastia include chronic liver disease, kidney failure, and exposure to estrogens, androgens (often taken secretly for body building), marijuana, and some medications. Rare causes include tumors, genetic defects, or an overactive thyroid.

Causes

• Puberty
• Exposure to estrogen hormone
• Exposure to androgen hormones
• Marijuana use
• Tumors
• Genetic disorders
• Chronic liver disease
• Kidney failure
• Side effects of some medications

Review Date: 2/2/2004
Reviewed By: Tarun Jain, M.D., Endocrinology & Infertility Division, Brigham and Women's Hospital, Boston, MA. Review provided by VeriMed Healthcare Network.