[A renal cell carcinoma mimicking a multilocular renal cyst]

A 38-year old man was admitted to the hospital for an investigation of abnormal ultrasonographic findings of the left kidney. Ultrasonography demonstrated multiple, fluid-filled masses separated by a highly echogenic septa and CT revealed a large cystic mass and a thick, irregular wall in the upper and middle poles. Selective, left renal arteriography showed a hypovascular mass. Thus, a presumptive diagnosis was made of multilocular renal cysts. Taking into accounted the possibility of a renal cell carcinoma. Surgical exploration and a left nephrectomy was performed. Microscopically, a multiloculated renal cell carcinoma thus was diagnosed, A definite, preoperative diagnosis is very difficulty to make in most cases, and surgical exploration is considered to be the only way to achieve an accurate diagnosis. Treatment for a multiloculated cystic renal mass containing multilocular renal cysts is a total or partial nephrectomy.