Multiple endocrine neoplasia (MEN) syndrome is the name given to abnormal over-secretion of hormones by different endocrine glands due to gene mutation, and thus causing different effects depending on the over-secreted hormone.
MEN SYndrome (Audio)
Types
There are 4 types.
1. MEN-1 (aka Wermer syndrome)
2. MEN-2a (aka Sipple syndrome)
3. MEN-2b (MEN 2b was previously called MEN 3.)
4. MEN-4
Mode of transmission
All MEN syndromes are autosomal dominant.
Pathology
MEN-1 and MEN-4 are caused by loss of function mutation of MEN-1 and CDNK1B genes, respectively.
MEN-2 are caused by gain of function mutation in the RET proto-oncogene.
Abnormalities
MEN-1: Primary hyperparathyroidism, Pituitary tumors like prolactinoma, and pancreatic neuroendocrine tumors, like insulinoma, gastrinoma etc.
MEN-2a: Primary hyperparathyroidism, Medullary thyroid carcinoma, and pheochromocytoma.
MEN-2b: Medullary thyroid carcinoma, pheochromocytoma and primary hyperparathyroidism as like in MEN-2a, but it also includes multiple mucosal neuromas. The patient has marfanoid body habitus, skeletal abnormalities, and abnormal dental enamel. Furthermore, as compared to MEN-2a, Medullary thyroid carcinoma occurs at an earlier age in MEN-2b.
MEN 4: MEN-4 is rare and abnormalities in this syndrome include primary hyperparathyroidism, pituitary tumors, and possible tumors in the adrenal glands, reproductive organs, kidneys, and pancreatic neuroendocrine tumors.
Treatment & Follow up
Treatment depends on the involved hormonal gland.
In most cases, surgical treatment such as parathyroidectomy is needed. In MEN 2, the incidence of medullary thyroid carcinoma is almost 100%, so thyroidectomy is done early.
Follow-up is required in all cases, to see for recurrence or the development of other gland tumors.
Genetic testing of family members is also needed, for early detection of medullary thyroid carcinoma, and prophylactic thyroidectomy.
