Multiple endocrine neoplasia (MEN) II

Definition

Multiple endocrine neoplasia II (MEN II) is an uncommon condition passed down through families (inherited), in which the thyroid, adrenal, and parathyroid glands are overactive.

See also: MEN I

Alternative Names

Sipple's syndrome

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. The adrenal tumor is called a pheochromocytoma, and the thyroid tumor is a medullary carcinoma of the thyroid.

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 similar subtypes of MEN II -- MEN IIa and IIb. MEN IIb is less common.

Symptoms

• Abdominal pain
• Back pain
• Chest pain
• Cough
• Cough with blood
• Depression
• Diarrhea
• Fatigue
• Heart palpitations
• Increased thirst
• Increased urine output
• Irritability
• Loss of appetite
• Muscle weakness
• Nausea
• Nervousness
• Personality changes
• Rapid heart rate
• Severe headache
• Sweating
• Weight loss

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

• Hyperparathyroidism
• Medullary carcinoma of the thyroid
• Pheochromocytoma

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.

A physical examination may reveal:

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

Diagnostic tests are used to evaluate the function of each endocrine gland. The following tests may be performed:

• Abdominal CT scan
• Adrenal biopsy
• Calcitonin
• Electrocardiogram (ECG)
• Imaging of the kidneys or ureters
• MIBG scintiscan
• MRI of abdomen
• Parathyroid biopsy
• Radioimmune assay of parathyroid hormone
• Serum alkaline phosphatase
• Serum calcium
• Serum phosphorus
• Thyroid biopsy
• Thyroid scan
• Ultrasound of the thyroid
• Urine catecholamines
• Urine metanephrine

Treatment

Surgery is needed to remove both the medullary carcinoma of the thyroid and the 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.

Surgery to remove the thyroid before it becomes cancerous is often being performed at an early age (before age 5) in people with known MEN IIa, and before age 6 months in people with MEN IIb.

Family members should be screened for the RET gene mutation.

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 complication.

Calling your health care provider

Call your health care provider if you notice symptoms of MEN II.

Prevention

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

References

Kronenberg HM. Plyglandular disorders. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 250.