MEN Syndromes

Multiple endocrine neoplasias (MEN) are a group of inherited disorders in which endocrine glands are either overactive or form a tumor. MEN I, sometimes referred to as Wermer syndrome, is a rare disease caused by a defect in the RET gene. Because it is genetic, it can be inherited and may occur in several members of a family. Risk factors for MEN I include an endocrine disorder or an endocrine tumor (i.e. a pituitary tumor, Zollinger-Ellison syndrome). Many of the tumors that form in MEN syndromes are benign, but it is possible for tumors associated with MEN I syndrome to become cancerous.

In this syndrome, tumors occur on various endocrine glands. As its name implies, at least 2 glands will be affected in this syndrome. However, more than two glands may be affected and tumors of the glands may occur concurrently or at different times in a person's life. There are three glands at highest risk for tumor growth in MEN I (although other glands may be invlolved as well. These include: the parathyroid glands, the pancreas, and the pituitary gland.

Parathyroid gland tumors associated with MEN I are parathyroid adenomas. These are benign (non-malignant) tumors that produce excess levels of parathyroid hormone. The high parathyroid hormone levels result in high calcium blood test and high calcium symptoms. High calcium symptoms include kidney stones, bone pain, fatigue, irritability or mood changes, muscle weakness, abdominal cramping and many others. In addition to high calcium symptoms, irreversible damage to the bones and heart may occur due to high parathyroid hormone levels.

Pancreas tumors associated with MEN I include insulinomas, gastrinomas, and vipomas. An inslulinoma is a tumor that produces too much insulin and results in very low glucose levels in the blood. A gastrinoma (this tumor results in a syndrome known as Zollinger-Ellison Syndrome) results in the production of too much acid in the stomach and can lead to stomach ulcers and/or bleeding. A vipoma produces VIP (vasoactive intestinal peptide) which can result in watery diarrhea and dehydration.

The pituitary gland is located at the base of the brain and produces many hormones that control multiple organs in the body. A pituitary tumor associated with MEN I can cause a wide variety of symptoms depending on the type of tumor formed. Will all pituitary tumors, symptoms may include headaches and changes in vision.

When a person has an isolated parathyroid disease diagnosis, MEN syndromes are not suspected unless there is a family history. However, if a patient has disease of more than one endocrine gland, a work-up for a MEN syndrome is necessary.