Gynecomastia is a condition in which firm breast tissue forms in males. The breast tissue is usually less than 1-1/2 inches across and is located directly under the nipple. Gynecomastia may be present on one side or on both sides. This condition may make the breast tender.

Some men and boys have fat on their chests that makes it look like they have breasts. This condition is called pseudogynecomastia (false gynecomastia). It is not the same thing as gynecomastia.

What causes gynecomastia?

Gynecomastia is usually caused by changes in hormones at puberty or as part of aging. Hormones are chemicals produced by the glands of the body, such as the thyroid gland, the testes and the ovaries. Gynecomastia may be caused by changes in the balance of 2 hormones, estrogen and testosterone. In rare cases, gynecomastia is caused by prescription drugs, over-the-counter medicines, illegal drugs, tumors or disease.

Are tests needed to find the cause of gynecomastia?

Sometimes tests are needed, and sometimes they’re not. Your doctor will ask you questions about your symptoms, such as how long you’ve had the breast tissue, and whether or not the area is tender. Your doctor will also ask you about the illnesses you have had in the past, the medicines you take, and other matters relating to your health. Then you will have a physical examination.

Whether you need tests depends on your age and what your doctor learns from your history and physical examination. If you are a teenager, you probably will not need more tests, since gynecomastia is very common in the teen years. As many as 65% of 14-year-old boys have gynecomastia. The breast enlargement usually goes away on its own in 2 or 3 years. However, boys and adult men with gynecomastia need to have some tests, because it is more possible in young boys and men that some kind of disease is causing the problem.

How is gynecomastia treated?

In most cases, no treatment is needed. Your doctor will probably want to check the size of your breast tissue every few months. In 90% of teenage boys, gynecomastia goes away in less than 3 years.

Sometimes the problem can be solved if you stop taking a medicine that is causing gynecomastia or stop using an illegal drug that is causing the problem.

Occasionally, medicines may be used to treat gynecomastia, especially if tenderness is a problem. The medicine will make the extra breast tissue go away. Rarely, surgery may be necessary to remove the extra breast tissue.

Treatment is necessary if gynecomastia is caused by a disease or a tumor. If it is due to a disease, the disease itself will need to be treated.

Could the breast lump be cancer?

Probably not. Breast cancer is very rare in males. Your doctor will probably be able to tell whether the lump is cancer. Lumps caused by cancer are usually not underneath the nipple, but breast tissue from gynecomastia grows in this area. Breast cancer feels different than the breast tissue of gynecomastia. With cancer, there sometimes is dimpling of the skin or a bloody discharge from the nipple. If there is any question that you have cancer, you will need to have a mammogram and a biopsy.