Renal hemangiopericytoma: surgical, radiological and pathological implications.

The first case of renal hemangiopericytoma presenting radiologically as a hypovascular mass is described. Preoperative diagnostic evaluation included ultrasonography, retrograde pyeloureterography, computerized tomography and angiography. Electron microscopy is helpful to distinguish this lesion from histologically similar juxtaglomerular cell tumors. Although renal hemangiopericytoma may appear benign on pathological examination it should be treated as a low grade malignancy and followed carefully.