RET and medullary thyroid gland carcinoma: There are three distinct variants associated with multiple endocrine neoplasia type 2 (MEN2): (1) MEN2A, which is characterized by medullary thyroid carcinoma, pheochromocytoma and primary hyperparathyroidism; (2) MEN2B, which in addition to medullary thyroid carcinoma and pheochromocytoma, patients may develop marfanoid habitus, or intestinal and mucosal ganglioneuromatosis and familial medullary thyroid carcinoma[1].