Mondo Description Multiple endocrine neoplasia type 2 (MEN2) is a multiple endocrine neoplasia, a polyglandular cancer syndrome characterized by the occurrence of medullary thyroid carcinoma (MTC), pheochromocytoma (PCC), in one variant, primary hyperparathyroidism (PHPT). There are three forms: MEN2A, MEN2B, and familial medullary thyroid carcinoma (FMTC).