Computed tomography of renal oncocytomas.

A retrospective analysis of 5 renal oncocytomas studied with CT was performed. Oncocytomas appeared as rounded hypodense solid masses with sharp margination from the normal renal parenchyma. They showed uniform homogeneous enhancement on CT scans performed after drip infusion of urographic contrast. One oncocytoma studied with dynamic CT scanning demonstrated a stellate (spoke-wheel) pattern of enhancement. No evidence of involvement of adjacent renal parenchyma, perinephric fat, renal veins or regional lymph nodes was present at CT and the findings were confirmed at surgery. Although the differential diagnosis between renal oncocytoma and hypernephroma may not be possible, preoperative awareness of a potentially benign lesion may guide the surgeon to attempt renal preserving surgery instead of the customary nephrectomy.