Germ cell tumors in the kidney are very rare, but when present are morphologically and immunophenotypically similar to germ cell tumors seen in the testis, ovary, retroperitoneum, and mediastinum. Pure teratoma can also occur in the kidney, mainly in prepuberal patients, rarely in adults. ¹ A metastasis must always be excluded when a germ cell tumor is encountered outside of the testis.