Gynaecomastia is enlargement of or change in consistency of the breast tissue in a male.
At birth, the breast consists of a button of tissue behind the nipple in both sexes. It is quite common at this time for these cells to be stimulated by hormones from the mother and for growth to occur, but this usually settles.
At adolescence, in females, hormones from the ovaries predominantly cause growth of the breasts, but clearly this does not happen in the male even though the similar breast cells are present. Males can however have an overflow effect due to metabolism of male hormones at this time leading to some growth of the cells, called pubertal gynaecomastia. Again this usually settles.
At any time in life any female hormone in a male, or an agent that looks like a female hormone to the receptors on the breast cells can lead to growth of the breast in a man. In general terms this is not dangerous or sinister but is commonly tender which is normal for breast tissue.
The commonest causes are other medications, obesity, liver disease, steroid ingestion, body building preparations, and cannabis. Rarer causes include testicular and adrenal tumours and genetic disorders.
No investigation or therapy is required for uncomplicated gynaecomastia. The enlargement can resolve but it commonly stays static. Some agents have limited effect but the effects must be balanced against untoward side effects such as acne, weight gain and hair growth which can be unacceptable. In general therefore we prefer to do as little as possible. Currently government directives deter us from offering cosmetic surgery for this condition.
Men can of course get breast cancer, but it is rare and usually occurs in older gentlemen, with a single painless lump in one breast. The investigation and treatment for this is very similar to that in the female.