Multiple Endocrine Neoplasia Types 1 and 2: Patient Education
The multiple endocrine neoplasia (MEN) syndromes are two types of inherited disorders that involve the predisposition to develop tumors in multiple different endocrine glands and sometimes other organs within your body.
There are two types of multiple endocrine neoplasia: Type 1 and Type 2. They are differentiated by the following:
- The specific change in a person’s genetic code that causes the condition
- The particular endocrine glands or other organs that are affected
- The hormones produced
Both forms of multiple endocrine neoplasia involve:
- two or more tumors forming within a particular affected endocrine gland
- tumors that form in multiple different endocrine glands in your body
The tumors may be noncancerous (benign) or cancerous (malignant).
Most of these tumors can be treated and often cured by surgery to remove them completely if they are detected early. Family testing and early diagnosis is therefore very important in patients who are suspected or known to be affected with one of these inherited conditions.
Your endocrine system is a system of glands and cells that make hormones that are released directly into your blood and travel to tissues and organs all over your body. Your endocrine system controls:
- Sexual development
Multiple Endocrine Neoplasia Type 1
Multiple endocrine neoplasia type 1 (MEN1) — also known as Wermer syndrome — is an inherited disorder in which one or more of your endocrine glands are overactive or form a tumor. Endocrine glands most commonly involved in MEN1 include:
- Islet cells (neuroendocrine cells) of your pancreas
- Parathyroid glands
- Pituitary gland
MEN1 tumors are usually noncancerous (benign), with the exception of some islet cell tumors and mediastinal carcinoid tumors, which can be cancerous (malignant).
Multiple Endocrine Neoplasia Type 2
Multiple endocrine neoplasia type 2 (MEN2) — also known as Sipple syndrome — is an inherited disorder in which one or more of your endocrine glands are overactive or form a tumor. Endocrine glands most commonly involved include:
- Thyroid gland (almost all of the time)
- Adrenal glands (about 50 percent of the time)
- Parathyroid glands (about 20 percent of the time)
Patients with MEN2 are predisposed to develop a specific type of thyroid cancer, called medullary thyroid cancer (MTC).
There are three classifications of MEN2:
- MEN2A – affects 60 to 90 percent of MEN2 families
- Medullary thyroid cancer — 90 to 100 percent of MEN2A are affected
- Pheochromocytoma (a typically noncancerous tumor of the adrenal glands) — 50 percent with MEN2A affected
- Parathyroid adenoma (noncancerous tumor) or increased size (hyperplasia) of the parathyroid gland — 5 to 10 percent with MEN2A affected
- MEN2B – affects 5 percent of MEN2 families
- Medullary thyroid cancer — 98 to 100 percent with MEN2B affected
- Pheochromocytoma — 50 percent with MEN2B affected
- Mucosal neuromas (noncancerous overgrowth of nerve tissue on tongue and lips) — 95 to 98 percent affected
- Muscle, joint and spinal problems — 95 percent affected
- Typical facial features, including swollen lips and thick eyelids — 75 to 90 percent affected
- Familial medullary thyroid cancer (FMTC) – affects 5 to 35 percent of MEN2 families
- Medullary thyroid carcinoma only
Sources: Gagel RF, Marx SJ. “Multiple endocrine neoplasia.” Williams Textbook of Endocrinology, Chapter 40, 11th ed., Philadelphia, 2008, and Eng C, Clayton D, et al. “The relationship between specific RET proto-oncogene mutations and disease phenotype in multiple endocrine neoplasia type 2. International RET mutation consortium analysis.” JAMA 276(19):1575-9, 11/1996.
In Our Health Library
More information on both types of multiple endocrine neoplasia (types 1 and 2):
More information about multiple endocrine neoplasia type 1 (MEN1):
More information about multiple endocrine neoplasia type 2 (MEN2):