Medullary microcarcinomas occurrence are rare and fortuitous, it's usually related to the calcitonin measurement, that's the gold standard for the diagnosis. In other cases performing a thyroidectomy for a benign thyroid disease it's found a sub-centimeter tumor. Actually it's not clear the most appropriate surgical treatment for those kind of tumors because the number of cases in literature is limited and because there are different surgical approaches. In this study 17 patients were operated for medullary thyroid microcarcinoma and the Authors found central lymph node metastases in 33.3% of cases. The Authors, analyzing those results, think that total thyroidectomy with lymphadenectomy of the central compartement is the best choice in a sporadic microcarcinoma, while a total thyroidectomy without lymphadenectomy should be performed when the microcarcinomas are incidentals.