Stellate scar sign of renal cell carcinoma

Stellate scar sign is defined as the centrally-placed, welldefined, stellate area of low density on computed tomography (CT) appearance of solid tumors. This kind of radiating enhancement from the center of the tumor, which is also referred as “a spoke-wheel-like enhancement” or central scar sign, usually has been recognized as a specific finding of renal oncocytoma. We describe a patient who developed clear cell renal cell carcinoma (RCC) displaying typical stellate scar sign on CT scans, which was confirmed by gross pathologic appearance. A 62-year-old Chinese man presented with incidentally detected renal tumor with once ignored gross hematuria half a year ago. Ultrasonography found a 5.6 cm hypoecho mass; CT scans displayed a nearly circular circumscribed mass in the middle of the left kidney, with inhomogeneous enhancement during corticomedullary and nephrographic phases, being an excellent likeness with a spoke wheel (Fig. 1). His medical history was not significant except that he had been a heavy smoker for more than 40 years. Laparoscopic nephrectomy of the left kidney surgery was performed for a presumed RCC and the patient recovered uneventfully in postoperative period. The central stellate scar on CT corresponded to fibrous connective tissue on the gross pathological examination; and the color of viable tumor tissue on cross-section is yellow cast of classical clear cell RCC, but not mahogany color of typical renal oncocytoma (Fig. 2). Histological examination arrived at the diagnosis of clear cell RCC.