INSULAR CARCINOMA - AN INFREQUENT SUBTYPE OF THYROID-CANCER

Background: Insular carcinoma is a little-known thyroid cancer, charac terized by the presence of well-defined nidi of small uniform cells wi th frequent areas of tumor necrosis and microfollicles with thyroglobu lin. It was described by Carcangiu in 1984, but its prognosis is not y et clear. Study Design: Six of 335 patients undergoing surgery for thy roid carcinoma had the insular type. We studied age, gender, treatment , histology (tumor size, coexistence of another tumor, extrathyroid sp read, vascular invasion, multicentricity, and metastatic adenopathies) , TNM, and followup (recurrences, mortality; and survival). These resu lts were compared with those published in the literature. Results: Ins ular carcinoma was more common in women (4 of 6), and mean patient age was 32 years. Three patients had metastatic adenopathies. Four patien ts presented with other thyroid tumors (2 papillary, 1 follicular, and 1 anaplastic) and 2 were simple. Two patients had vascular invasion, and another 2 were extrathyroid. Only 1 case was multicentric. Three r ecurrences were detected in 2 patients over 50 years old: 1 lymph node at 60 months, 1 pulmonary at 132 months, and the other a bone recurre nce at 8 months. Two patients died at 12 and 140 months. Conclusions: Insular carcinoma is a special type of thyroid cancer, and the prognos is is poorer than for the classic differentiated thyroid carcinoma (J Am Cell Surg 1998;187:503-508. (C) 1398 by the American College of Sur geons).