An Overview of Multiple Endocrine Neoplasias

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Multiple endocrine neoplasia (MEN) is the name for a group of hereditary illnesses characterized by having more than one tumor of the endocrine organs at a time.

Several different combinations of endocrine tumors are known to occur together, and each of these patterns is categorized as one of several different MEN syndromes.

Doctor checking thyroid glands

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Multiple endocrine neoplasia syndromes can affect these major endocrine glands:

  • Adrenal
  • Pancreas
  • Parathyroid
  • Pituitary
  • Thyroid

The tumors that develop as part of each MEN syndrome may be benign or malignant. Benign tumors are abnormal tumors that can cause medical symptoms but grow slowly, do not spread to other parts of the body, and are not fatal.

Malignant tumors are cancerous tumors that can grow rapidly, may spread to other parts of the body, and can be fatal if they are left untreated.


Each of the three syndromes that are considered the most common manifestations of MEN is caused by a specific genetic abnormality, and the tumor combination often runs in families as a hereditary condition.

This condition is inherited in an autosomal dominant pattern. About 50% of children of people with MEN syndromes will develop the disease and 50% won't.

Furthermore, a person with a family history MEN cannot pass it on to their children unless they themselves have inherited the gene that causes MEN. In other words, if one of your parents has MEN, but you do not, your children have no risk of getting the disease.

Types and Symptoms

The MEN syndromes are called MEN 1, MEN 2A, and MEN 2B (which was formerly called type 3). Each has a unique set of symptoms to consider.

Tumor location depends on the type of MEN syndrome.


People diagnosed with MEN 1 have tumors of the pituitary gland, the parathyroid gland, or the pancreas. Generally, these tumors are benign, although it is not impossible for them to become malignant.

The symptoms of MEN 1 can begin during childhood or adulthood. The symptoms are variable because the tumors involve endocrine organs that can produce a wide range of effects on the body. Each of the tumors causes abnormal changes related to hormonal overactivity. Possible symptoms of MEN 1 include:

  • Difficulty breathing
  • Headaches, high blood pressure, irregular heartbeat, and panic attacks
  • Hyperparathyroidism, in which the parathyroid gland produces too much hormone, and can cause tiredness, weakness, muscle or bone pain, constipation, kidney stones, or thinning of bones. Hyperparathyroidism is usually the first sign of MEN1 and typically occurs between the ages of 20 and 25. Nearly everyone with MEN1 will develop hyperparathyroidism by the age of 50.
  • Irregular periods in women; reduced sexual desire or erectile dysfunction in men
  • Nausea, diarrhea, and vomiting


People with MEN 2 have thyroid tumors, adrenal gland tumors, or parathyroid tumors. The symptoms of MEN 2A begin during adulthood, typically when a person is in their 30s. As with the other MEN syndromes, the symptoms result from overactivity of the endocrine tumors and include:

  • Chest pain
  • Frequent urge to urinate
  • Headaches
  • High blood pressure
  • Rapid heartbeat
  • Sweating

Itch May Develop

People with MEN 2A sometimes develop an itchy skin condition called cutaneous lichen amyloidosis.


As the least common of these rare tumor patterns, MEN 2B is characterized by thyroid tumors, adrenal gland tumors, neuromas throughout the mouth and digestive system, abnormalities of bone structure, and an unusually tall and skinny stature with long fingers, toes, arms, and legs. Together, these features are known as marfanoid habitus.

Other symptoms can begin in childhood, often before age 10, and include:

  • Nerve pain
  • Stomach and digestive problems
  • Symptoms of thyroid cancer and pheochromocytoma (a rare and usually noncancerous tumor)


Your healthcare provider may be concerned that you may have MEN syndrome if you have more than one endocrine tumor and your family history includes people with the syndrome. You do not need to have all of the signature tumors of one of the MEN syndromes for your healthcare provider to consider the disease. If you have more than one tumor or characteristic, or even if you have one endocrine tumor that is associated with MEN, your healthcare provider may evaluate you for other tumors before they become symptomatic.

A family history is not necessary for MEN diagnosis because a person can be the first in the family to have the disease. The specific genes that cause MEN have been identified, and genetic testing may be an option in confirming the diagnosis.

Diagnostic tests may include:

Thyroid Disease Doctor Discussion Guide

Get our printable guide for your next healthcare provider's appointment to help you ask the right questions.

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The treatment for the MEN syndromes depends on several different factors. Not everyone who is diagnosed with MEN 1, MEN 2A, or MEN 2B experiences the same exact disease course. Generally, treatment is focused on three main objectives: reducing symptoms, detecting tumors early, and preventing the consequences of malignant tumors.

If you are diagnosed with one of the MEN syndromes, your treatment will be customized to your particular needs. One or more of the following therapies may be recommended to treat the disease or help relieve symptoms.

  • Medications to help balance hormone levels or treat symptoms
  • Surgical removal of the affected gland to treat symptoms (Hyperparathyroidism caused by MEN1 is typically treated with surgical removal of three-and-a-half of the four parathyroid glands, although sometimes all four glands are removed.)

Active surveillance and monitoring to identify new tumors and to spot any malignancy as early as possible may also be recommended.


Multiple endocrine neoplasia (MEN) is the name for a group of hereditary illnesses characterized by having more than one tumor of the endocrine organs at a time. MEN syndromes can affect the major endocrine glands: adrenal, pancreas, parathyroid, pituitary, and thyroid. The tumors that develop as part of each MEN syndrome may be benign or malignant. Symptoms vary, and the success of treatment often depends on how early the disease is detected.

A Word From Verywell

Finding out you have a tumor is distressing, and having more than one tumor is even more frightening. If you have been told that you have multiple endocrine neoplasia, then you are probably quite concerned about which symptoms could emerge next and whether your overall health is in danger.

The fact that MEN syndromes are recognized and classified makes your situation more predictable than it may seem. Despite the fact that these are rare syndromes, they have been defined in great detail. Plus, there are well-established methods for managing these illnesses. While you will certainly need consistent medical follow-up, there are effective ways to control the condition. And with prompt diagnosis and appropriate treatment, you can live a healthy life.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. University of Texas. Anderson Cancer Center. Multiple endocrine neoplasia.

  2. EndocrineWeb. M.E.N. Syndromes: Multiple endocrine neoplasia.

  3. National Library of Medicine. MedlinePlus. Multiple endocrine neoplasia.

  4. National Center for Advancing Translational Sciences. Multiple endocrine neoplasia type 1.

  5. National Center for Advancing Translational Sciences. Multiple endocrine neoplasia type 2A.

  6. National Center for Advancing Translational Sciences. Multiple endocrine neoplasia type 2B.

  7. Multiple endocrine neoplasia type 1.

Additional Reading

By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.