RET and primary hyperparathyroidism: Furthermore, medullary thyroid carcinoma is a component of multiple endocrine neoplasia type 2 syndrome (MEN2A and MEN2B) in 25% of cases, suggesting that the preoperative assessment of mutations in the RET proto-oncogene, and screening for primary hyperparathyroidism and pheochromocytoma should be performed, and the minimal surgery extent should involve a total thyroidectomy and prophylactic central neck dissection [6].