Update on multiple endocrine neoplasia Type 1 and 2.

Multiple endocrine neoplasia type 1 is a rare genetic syndrome, characterized by the co-occurrence, in the same individual or in related individuals of the same family, of hyperparathyroidism, duodenopancraetic neuroendocrine tumors, pituitary adenomas, adrenocortical tumors, and neuroendocrine tumors (carcinoids) in the thymus, the bronchi, or the stomach. Multiple endocrine neoplastic type 2 is a rare genetic syndrome, characterized by the familial occurrence of medullary thyroid carcinoma either isolated or associated with pheochromocytoma, primary hyperparathyroidism, or typical features (Marfanoid habitus, mucosal neuromas). Subjects with clinical MEN1 and those who carry a mutation in the MEN1 gene should be offered biochemical and imaging screening in order to detect tumors and evaluate their progression over time. Children with mutation in the RET gene should have prophylactic total thyroidectomy according to the category of aggressiveness of the detected mutation whereas those with clinical MEN2 should be operated on upon diagnosis. In MEN1 patients, special attention should be paid to evaluate the progression duodenopancraetic neuroendocrine tumors because of their malignant potential. Also, thymic neuroendocrine tumors should be detected as soon as possible because they represent the most lethal tumor. In MEN2, calcitonin and carcinoembryonic antigen (CEA) serve as excellent tumor markers for medullary thyroid carcinoma. Their preoperative levels are correlated with tumor size and predict postoperative cure. Moreover, calcitonin or CEA doubling time has important prognostic value. In both MEN syndromes, multidisciplinary approaches are very important in the care of affected patients. Moreover, those patients should be comprehensively informed and enabled to participate in the decision-making procedure. In addition to multidisciplinary approaches, every effort should be made to follow the recommendations and guidelines issued by national (the French Group of Endocrine Tumors) and international groups.