[Prophylactic thyroidectomy in multiple endocrine neoplasia syndrome].

Multiple endocrine neoplasia (MEN) 2a consists on medullary thyroid carcinoma, pheochromocytoma and hyperparathyroidism. The identification of the RET proto-oncogene in 1993 has changed the prognosis of the disease. We have retrospectively studied the patients diagnosed of MEN 2a in our centre for the last 7 years in order to establish the most adequate age to undergo surgery. We present ten patients diagnosed with MEN 2a, whose ages ranged from 1.5 to 11 years old. Mean age at time of operation: 6,4 years An ultrasound study, calcitonin determinations and cathecholamines and urinary metanephrine levels were obtained before surgery. The surgical treatment is based on total total thyroidectomy, in selected cases lymph node resection in the central zone lf the neck. The most frequent RET mutation is the one affecting codon 634 (exon 10), which was found in children. Both of them had an alteration in codon 611 (exon11). No complications appeared after surgery and hospital discharge took place in the 2nd-4th day after surgery. Pathological findings were medullary thyroid microcarcinoma (MTMC) in 3 out of 10 patients, calcitonin preoperative tests were high in one of them. No tumoral cells were found in the lymph nodes. During the follow up period, 9 out of 10 from the operated patients, maintained normal calcitonin, CEA, PTH, calcium, cathecholamines and urinary metanephrine levels. Since there are 3 cases of MTC in patients between 3 and 6 years old, and diagnostic test data are not conclusive, we thoroughly recommend prophyilactic thyroidectomy at early ages, from 3 to 4 years old.