Insular carcinoma(poorly differentiated thyroid cancer) is defined as a aggressive, follicular-derived thyroid carcinoma with behavior intermediate between follicular/papillary and anaplastic carcinomas. It was described by Carcangiu in 1984, but its prognosis, classification and the origin is not yet clear. And preoperative fine needle aspiration cytology of insular carcinoma has not been satisfactory. We experienced a case of advanced thyroid insular carcinoma with invasion of the sternum. So we intend to present the case with a review of the related literatures.