Malignant fibrous histiocytoma of the kidney

Primary renal malignant fibrous histiocytoma (MFH) is a rare tumor indistinguishable from renal cell carcinoma clinically and radiologically which can be differentiated only by histological and immunohistochemical studies. We report a case of primary renal MFH in a 40-year-old female who presented with left flank pain. Abdominal ultrasonography and computerized tomography revealed a well-defined renal mass. The contralateral kidney and renal functions were normal. Preoperative diagnosis was renal cell carcinoma and nephrectomy was performed. Histological examination and immunohistochemistry revealed MFH.