Papillary thyroid carcinoma-like tumor of the kidney: a case report.

Thyroid carcinoma-like tumor of the kidney is an extremely rare variant of renal cell carcinoma. Most previously reported cases were incidental finding; and none of them showed papillary thyroid carcinoma (PTC) nuclear features. This study reports the first case of PTC (follicular variant)-like tumor of the kidney in which a female patient presented with hematuria, weight loss, and flank pain. Imaging studies revealed a left renal mass with enlarged hilar lymph nodes. Histologically, the renal tumor had a striking resemblance to follicular variant of PTC. However, no radiological abnormalities were found in the thyroid, mediastinum, or pelvis. Tumor cells were negative for thyroid markers (thyroglobulin and TTF1). According to the authors, this is the first case of PTC (follicular variant)-like tumor of the kidney.