What could cause my breasts to become larger?

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Q. My breasts have begun to feel swollen and seem larger. What could cause this, and should I be worried about any potential health issues?

A. Swollen breasts in men are almost always caused by either one or both of two conditions: excess fat deposition in the breasts, or growth of actual glandular breast tissue (gynecomastia). Fatty deposition occurs in overweight men and is always present in both breasts. With gynecomastia, the breasts have a firm or rubbery consistency. While it usually affects both breasts, it can affect one breast much more than the other.

While gynecomastia can be embarrassing, it rarely has a serious cause. However, in adult men, the condition warrants a medical evaluation to look for possible health issues. The most common identifiable cause is a drug side effect. Examples include the diuretic spironolactone (Aldactone); finasteride (Proscar) or dutasteride (Avodart), which help shrink a large prostate gland; stomach acid blockers like cimetidine (Tagamet) and ranitidine (Zantac); and hormonal drugs to treat prostate cancer.

A majority of the time, your doctor won't find a reason for your gynecomastia. In these instances, there is no available treatment. If your breast enlargement is due to increased fat, your best chance to reduce breast size is weight loss.

— by Howard LeWine, M.D.
Editor in Chief, Harvard Men's Health Watch