Oncocytoma

Renal oncocytoma is a benign renal neoplasm that makes up 6% to 9% of all renal tumors. It is usually asymptomatic and is most often discovered incidentally on imaging studies performed for unrelated conditions. The tumor is usually well-circumscribed but not encapsulated. It has characteristic mahogany brown or yellow-brown color. A prominent central stellate scar is seen in about 30% of cases, usually in larger tumors.