Malignant metastatic perirenal schwannoma.

Only seven cases of malignant renal or perirenal schwannomas have previously been reported in the literature. Herein we report the case of a 74-year-old female with a previous history of malignant subcutaneous schwannoma and breast ductal adenocarcinoma who presented with a renal mass that was preoperatively diagnosed as a metastatic schwannoma. This is the first case of malignant perirenal schwannoma of metastatic origin.