Multiple Endocrine Neoplasia Type 2 and Familial Medullary Thyroid Cancer

Multiple endocrine neoplasia type 2 (MEN2) causes tumors to develop in endocrine glands, particularly the thyroid, parathyroid, and adrenal glands. MEN2 can affect young children.

Without prevention, individuals with MEN2 will almost certainly develop medullary thyroid cancer. The tumors that develop in the adrenal and parathyroid glands are generally benign but cause excessive hormone production.

Adrenal gland tumors, called pheochromocytomas, can cause high blood pressure and otherwise unexplainable anxiety or sweating. Excessive levels of parathyroid hormone cause bones to become weak and kidney stones to form.

There are different types of medullary thyroid cancer: 

Familial Medullary Thyroid Cancer (FMTC)
No increased risk for adrenal or parathyroid tumors. Nearly everyone with FMTC will develop medullary thyroid cancer. 
MEN2A
Tends to develop in young adulthood. About half of these individuals will develop adrenal tumors, and one out of four will develop parathyroid tumors.
MEN2B
Develops in early childhood. About half of people with MEN2B develop adrenal tumors; parathyroid tumors are rare. They are more likely to develop benign overgrowths on their lips, tongue, and gastrointestinal tract. They are more likely to have a thinner and taller stature than their family members.

MEN2A, MEN2B, and FMTC are all caused by mutations in the RET gene. Whether people develop MEN2A, MEN2B, or FMTC is dependent on the type and location of the mutation within the RET gene.

Our cancer genetic counselors can speak with you about your risk of having MEN2 or FMTC, and can discuss and offer genetic testing. Genetic testing is used, in part, to determine who else in the family has MEN2 or FMTC. Each child of an individual who has a RET mutation has a 50 percent chance of also having the same mutation.

MEN1 and MEN2 are two separate conditions that should not be confused with each other.