Below is a summary of this disorder from the American Cancer Society.
Gynecomastia is the most common male breast disorder. It is not a tumor, but rather an increase in the amount of a man’s breast tissue. Usually, men have too little breast tissue to be felt or noticed. A man with gynecomastia has a button-like or disk-like growth under his nipple and areola, which can be felt and sometimes seen. Although gynecomastia is much more common than breast cancer in men, both can be felt as a growth under the nipple, which is why it’s important for me to have any such lumps checked by their health care providers.
Teenage Boys & Older Men
Gynecomastia is common among teenage boys because the balance of hormones in the body changes during adolescence. It is also common in older men due to changes in their hormone balance.
In rare cases, gynecomastia occurs because tumors or diseases of certain endocrine (hormone-producing) glands cause a man’s body to make more estrogen (the main female hormone). Men’s glands normally make some estrogen, but it is not enough to cause breast growth. Diseases of the liver, which is an important organ in male and female hormone metabolism, can change a man’s hormone balance and lead to gynecomastia. Obesity can also cause higher levels of estrogens in men.
Some medicines can cause gynecomastia. These include some drugs used to treat ulcers and heartburn, high blood pressure, and heart failure. Men with gynecomastia should ask their health care providers if any medicines they are taking might be causing this condition.
Klinefelter syndrome, a rare genetic condition, can lead to gynecomastia as well as increase a man’s risk of developing breast cancer.