Multiple endocrine neoplasia (MEN) is an inherited condition that causes growths (tumours) in endocrine glands. There are endocrine glands throughout the body. They make chemicals called hormones. These control many functions in the body and help keep it in balance.
There are two types of MEN: MEN1 and MEN2. Although their names are similar, they are completely separate conditions. This information is about MEN1.
Tumours caused by MEN1 are usually benign (non-cancerous). But they may make the gland they are growing in make too much hormone. This is the most common cause of symptoms in people with MEN1.
The endocrine glands that are most likely to be affected are:
- the parathyroid glands, which are in the front of the neck
- the pancreas, which is an organ behind the stomach
- the pituitary gland, which is at the base of the brain.
Tumours in these glands are called MEN1-associated endocrine tumours.
People with MEN1 may also develop tumours in other parts of the body. These are called MEN1-associated tumours. These include tumours in the adrenal glands, and in fatty tissue, connective tissue or blood vessels just under the skin.
A small number of people with MEN1 develop other growths in the bowel, lungs and thymus gland. These are called carcinoid tumours.
Tumours can develop at any age. About 4 in 10 people with MEN1 (40%) have a tumour by the time they are 20. About 8 in 10 people (80%) have a tumour by the age of 50.