Perirenal malignant Schwannoma presenting as renal cell carcinoma.

Clinical and radiographic evaluation of a fifty-six-year-old male with microscopic hematuria led to radical nephrectomy for renal cell carcinoma. Histologic examination by light and electronmicroscopy was most compatible with malignant schwannoma. The tumor was close to the kidney without actual renal involvement. This case is of interest for both its rarity and its unusual presentation.