Acromegaly is the name given to a condition caused by the body producing too much growth hormone (GH). The excess GH usually (about 95% of cases) comes from a non-cancerous tumour in the pituitary gland. It is a fairly rare disease with about 50 cases per million in the population. The increased amount of GH also leads to increased formation of another hormone, insulin-like growth factor (IGF-1).
The other 5% of cases of excess GH and acromegaly are caused by growth hormone-releasing hormone (GHRH) or GH being produced in tumours elsewhere in the body.