MEN2A includes MTC, pheochromocytoma, and hyperparathyroidism (due to parathyroid hyperplasia or multiple adenomas); MEN2B (more aggressive) combines MTC, pheochromocytoma, mucosal neuromas, and marfanoid habitus; and FMTC presents as isolated MTC without other endocrine tumors [2,3]. This evidence concerns the gene RET and parathyroid hyperplasia.