Sporadic Medullary Microcarcinoma of the Thyroid: A Retrospective Analysis of Eighty Cases

Clinical characteristics and prognosis of 80 patients (53 women and 27 men) with sporadic medullary thyroid carcinomas (MTC), less than 1 cm in size (micro-MTC), operated on between 1971 and 1996 are reported (73 total and 7 partial thyroidectomies). These patients, obtained from a national database of 899 patients with MTC, were compared with 357 cases of sporadic MTC greater than 1 cm and 149 subjects with familial MTC less than 1 cm (familial micro-MTC). Median age at surgery was 52.5 years, a distribution similar to larger sporadic MTC. Micro-MTC was identified due to elevated calcitonin (47.5%), clinically identified lymph node (10.0%), distant metastases (6.3%) or pathologic finding at surgery (36.2%). Diarrhea and/or flushing were observed in 6 patients including 4 with clinically identified lymph node. Among patients who had lymph node dissection at surgery (68.8%), lymph node involvement with tumor was observed in 30.9%, and was significantly more frequent in multifocal (7/11) than in unifocal mi...