Metastatic renal tumor originating from thyroid cancer: a case report

A 82-year-old female was referred to our department for close examination and treatment of a right renal tumor incidentally found by computed tomography. Her past history included partial thyroidectomy for follicular thyroid carcinoma 20 years earlier. Enhanced computed tomography showed a hypervascular mass with a diameter of 3 cm at the lower pole of the right kidney. We carried out radical nephrectomy for diagnosis of renal cell carcinoma. Pathological findings revealed a metastatic renal tumor of follicular thyroid carcinoma. It is rare to find metastatic renal tumors arising from thyroid carcinoma in clinical practice. Thirty cases have been reported in the Japanese literature.