Although the cause of gynecomastia is largely unknown some possible causes include: medicines (for high blood pressure, heart disease and prostate cancer), drugs (such as marijuana and anabolic steroids), some diseases (such as liver failure and some cancers) and some very rare congenital abnormalities.
It has been suggested that gynecomastia can also be caused by changes in hormone levels. In about 15 per cent of teens, higher levels of estrogen than testosterone can result in the growth of large puffy nipples to fully-fledged breasts that can fill a C cup-sized bra and in some cases, even capable of producing milk. All men have the male sex hormone testosterone as well as low levels of the female hormone estrogen which controls breast tissue growth.
When the testosterone to estrogen ratio changes (that is, there is an imbalance in the levels of these two hormones favoring relatively higher amounts of estrogen), breast tissue can grow. Some men with gynecomastia have elevated estrogen levels.
Gynecomastia can also be caused by genetic problems, chronic diseases (especially kidney and liver) or various drugs. Men who take anabolic steroids to enhance sporting performance or to help with body building often develop gynecomastia.
How would you know if you have gynecomastia? (Signs & symptoms)
Gynecomastia can appear as a small lump and becomes tender as the mass becomes larger. The growth of breast tissue can be accompanied by pain and tenderness. Rarely nipple discharge will occur. There could be mild discomfort during certain activities.
How is gynecomastia diagnosed?
A doctor can examine the enlarged breast tissue to check whether it is gynecomastia or excess fat. In true gynecomastia, a rubbery or firm mound of tissue the same shape as the nipple can be felt. This is different from the situation where breast enlargement is due to fatty tissue, when no round shaped disc of tissue is found.