Other rare complications arise from pituitary tumors that release high amounts of ACTH, which in turn stimulates the adrenal glands to produce excess cortisol. Pituitary tumors that produce growth hormone cause excessive bone growth or disfigurement. Another rare complication is an endocrine tumor inside the chest or in the stomach, known as a carcinoid. In general, surgery is the mainstay of treatment for all of these rare types of tumors, except for gastric carcinoids, which usually require no treatment. The overactive endocrine glands associated with MEN I may contain benign tumors, but usually they do not have any signs of cancer.
Benign tumors can disrupt normal function by releasing hormones or by crowding nearby tissue.
For example, a prolactinoma may become quite large in people with MEN1. As it grows, the tumor can press against and damage the normal part of the pituitary gland or the nerves that carry vision from the eyes. I is a plum-sized, fatty tumor called a lipoma, which grows under the skin. Lipomas cause no health problems and can be removed by simple cosmetic surgery if desired. These tumors are also fairly common in the general population.