A young man is found to have hyperparathyroidism, medullary thyroid carcinoma, and bilateral adrenal pheochromocytomas. Genetic testing reveals a germline gain-of-function mutation in the RET proto-oncogene. Which additional feature distinguishes his syndrome from MEN 2A?

• A Presence of parathyroid hyperplasia
• B Pancreatic islet cell tumors
• C Pituitary adenoma
• D Marfanoid habitus and mucosal neuromas ✓

Explanation

MEN 2B (also called MEN 3) is characterized by medullary thyroid carcinoma and pheochromocytoma (as in MEN 2A) but additionally features a marfanoid body habitus and mucosal neuromas of the lips, tongue, and gastrointestinal tract. Parathyroid hyperplasia is a feature of MEN 2A, not MEN 2B. Pancreatic islet cell tumors and pituitary adenomas are hallmarks of MEN 1, which involves mutations in the MEN1 (menin) gene.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.