Polycystic disease of the renal sinus: structural characteristics.

Based on a series of 32 identified cases the radiologic, sonographic and anatomic features of polycystic disease of the renal sinus are described. This entity is a bilateral accumulation of thin-walled clear fluid-filled cysts, intertwined with the caliceal infundibula and usually confused radiologically with adult polycystic kidney disease or with renal sinus lipomatosis. Computerized tomography and sonography demonstrate the parenchyma to be free of cystic disease and the hilus to be free of fat accumulation. This newly recognized entity has a completely benign natural history.