Multiple endocrine neoplasia (MEN) II

Definition

Multiple endocrine neoplasia, type II (MEN II) is disorder passed down through families in which one or more of the endocrine glands are overactive or form a tumor. Endocrine glands most commonly involved include:

• Adrenal gland (about half the time)
• Parathyroid gland  (20% of the time)
• Thyroid gland (almost all of the time)

See also: MEN I

Alternative Names

Sipple syndrome; MEN II

Causes, incidence, and risk factors

The cause of MEN II is a defect in a gene called RET. This defect causes many tumors to appear in the same person, but not necessarily at the same time.

A tumor in the adrenal gland is called a pheochromocytoma.

A tumor in the thyroid gland is a medullary carcinoma of the thyroid.

Tumors in the thyroid, adrenal, or parathyroid glands may occur years apart.

The disorder may occur at any age, and affects men and women equally. The main risk factor is a family history of MEN II.

There are two subtypes of MEN II -- MEN IIa and IIb. MEN IIb is less common.

Symptoms

The symptoms may vary. However, they are similar to those of:

• Medullary carcinoma of the thyroid
• Pheochromocytoma
• Parathyroid adenoma
• Parathyroid hyperplasia

Signs and tests

To diagnose this condition, the health care provider looks for a mutation in the RET gene. This can be done with a blood test. Additional tests are done to determine which hormones are being overproduced.

A physical examination may reveal:

• Enlarged lymph nodes in the neck
• Fever
• High blood pressure
• Rapid heart rate
• Thyroid nodules

Imaging tests used to identify tumors may include:

• Abdominal CT scan
• Imaging of the kidneys or ureters
• MIBG scintiscan
• MRI of abdomen
• Thyroid scan
• Ultrasound of the thyroid

Blood tests are used to see how well certain glands in the body are working. They may include:

• Calcitonin level
• Blood alkaline phosphatase
• Blood calcium
• Blood parathyroid hormone level
• Blood phosphorus
• Urine catecholamines
• Urine metanephrine

Other tests or procedures that may be done include:

• Adrenal biopsy
• Electrocardiogram (ECG)
• Thyroid biopsy
• Parathyroid biopsy

Treatment

Surgery is needed to remove pheochromocytoma.

For medullary carcinoma of the thyroid, the thyroid gland and surrounding lymph nodes must be totally removed. Thyroid hormone replacement therapy is given after surgery.

If a child is known to carry the RET gene mutation, surgery to remove the thyroid before it becomes cancerous is considered. This should be discussed with a physician who is very familiar with this condition. It would be done at an early age (before age 5) in people with known MEN IIa, and before age 6 months in people with MEN IIb.

Support Groups

Expectations (prognosis)

Pheochromocytoma is usually not cancerous (benign). Medullary carcinoma of the thyroid is a very aggressive and potentially fatal cancer. However, early diagnosis and surgery can often lead to a cure.

Complications

The spread of cancerous cells is a possible complication.

Calling your health care provider

Call your health care provider if you notice symptoms of MEN II or if someone in your family receives such a diagnosis.

Prevention

Screening close relatives of people with MEN II may lead to early detection of the syndrome and related cancers.

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References

Kronenberg HM. Polyglandular disorders. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 239.

National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology: Neuroendocrine Tumors. National Comprehensive Cancer Network; 2011. Version 1. 2011.