4th April 2024

MEN-2

Background

MEN-2 is extremely rare. MEN-2a and 2b both are associated with a high risk for early onset medullary thyroid carcinoma and phaeochromocytomas. Phaeochromocytomas can be screened with serum free metanephrines and normetanephrines. MEN-2a, in addition, has an increased association with parathyroid adenomas or hyperplasia.

Diagnosis

• MEN2A is diagnosed clinically by 2 or more specific endocrine tumours
• MEN2b is diagnosed clinically with medullary thyroid carcinoma < 40 years old, mucosal neuromas and a marfanoid habitus 
• If clinical features are inconclusive, RET genetic testing can be used

Treatment

Treatment for medullary thyroid carcinoma is thyroidectomy and lymph node dissection. However, patients with the RET gene may be offered a prophylactic thyroidectomy and then follow up calcitonin levels. Calcitonin is released by C cells of the thyroid and it opposes the action of PTH. Phaeochromocytomas are removed by adrenalectomy.

The table below summarises the features of the main types of MEN: