The male breasts
Men have a small amount of breast tissue where breast cancer can develop. If you are worried about any changes, always talk to your GP.
Men have a small amount of breast tissue behind their nipples, where breast cancer can develop.
Until puberty, breast tissue in boys and girls is the same. Both have a small amount of breast tissue behind the nipple and areola (the darker area of skin around the nipple). This is made up of a few tiny tubes (ducts) surrounded by fatty tissue, connective tissue, blood vessels and lymphatic vessels.
At puberty, both girls and boys start to produce the hormone oestrogen. In girls, this leads to breast tissue developing. In some boys, oestrogen also causes breast swelling. But this is usually temporary and their breast tissue does not develop.
At the same time, boys start making more of the hormone testosterone. This acts against the effects of oestrogen.
The balance between these hormones can also be affected as men get older, or as a side effect of certain drugs. Other health conditions can also affect the hormone balance, such as chronic liver disease, obesity and an overactive thyroid gland (hyperthyroidism). This can cause breast tissue to swell (called gynaecomastia). This is not linked with breast cancer.
If you are worried about any changes, always talk to your GP.