As discussed in Understanding Multiple Endocrine Neoplasia, MEN is a group of hereditary disorders that causes tumors to grow in the body’s endocrine organs, the glands that produce hormones. MEN is separated into two distinct types: Type 1 and Type 2. This article focuses on MEN Type 2.
Multiple Endocrine Neoplasia Type 2a Symptoms
Because medullary thyroid cancer will affect almost all of the patients with MEN type 2a, symptoms related to growth in the thyroid gland are common. Because of the thyroid gland’s location in the neck, patients can become hoarse or have difficulties with swallowing or breathing.
Pheochromocytomas, the tumors of the adrenal gland that will affect about half of patients with MEN type 2a, overproduce “stress hormones” like adrenaline. Excessive adrenaline raises the blood pressure, quickens the pulse (which the patient can sometimes feel as a “racing heart” or palpitations), causes sweating, and may also cause headache. These symptoms tend to come and go in an unpredictable fashion.
Finally, the MEN type 2a patients are prone to the same problems associated with high calcium levels and hyperparathyroidism seen in MEN type 1.
Multiple Endocrine Neoplasia Type 2b Symptoms
In type 2b, patients tend to be tall and thin, with a narrow face, long fingers, and very flexible joints. Bumps can appear over their lips, tongues, and inner cheeks; these bumps are called mucosal neuromas. Patients with MEN type 2b almost never develop problems with their parathyroid glands.
These patients have similar symptoms to MEN type 2a, but rarely have problems with high calcium level. Instead, they can have severe difficulties with slowed digestion and constipation. In addition to the bumpy growths around and in their mouths, they can have visual problems due to early cataract formation, which clouds the lens at the front of the eye and interferes with transmission of light to the back of the eye.
Surgery in MEN2
It is appropriate for the treatment of MEN2 patients to involve surgery, and sometimes multiple operations.
The timing of preventive (or prophylactic) removal of the thyroid gland (thyroidectomy) requires careful consideration of the specific RET mutation that has resulted in the MEN2 syndrome. Certain mutations put even very young children at risk for medullary thyroid cancer, and infants at highest risk sometimes undergo surgery during the first year of life. A collaborative effort between a genetic counselor and an endocrine surgeon is usually needed to plan these surgeries. RET mutations that carry a lower risk for early, aggressive thyroid cancer may allow surgery to be postponed to later in childhood or young adulthood.
At the time of thyroid surgery, the adjacent parathyroid glands may also be evaluated and some of the glands can be removed if there is suspicion for hyperparathyroidism. Again, deciding which of the 4 glands should be cut out relies on the expertise of the surgeon, who can do sophisticated testing before and during the operation to isolate which glands are contributing the most to high calcium levels. Since MEN1 and MEN2a predispose all 4 parathyroid glands to eventually becoming overactive, the surgeon will sometimes “auto-transplant” the parathyroid glands from the neck to a location in the arm, where they are more accessible for future treatments.
Finally, the surgical approach to the MEN2 patient can involve removal of one or both adrenal glands if there is concern for pheochromocytoma. Because these tumors release chemicals that can have dramatic effects on blood pressure, they have to be approached very carefully. Even biopsies of suspected pheochromocytomas can merit the patient taking medications beforehand to regulate their blood pressure. Also, if pheochromocytoma and medullary thyroid cancer exist in the same patient at the same time, the pheochromocytoma is frequently taken out first to avoid complications with blood pressure during the operation to remove the thyroid. The refinement of surgical techniques means that part of the normal adrenal gland can sometimes be left behind (this is called “cortex-sparing adrenalectomy”) so that the patient can continue to benefit from the functions of that organ even after their pheochromocytoma has been removed.