[Cystic renal cell carcinoma: report of four cases].

We report 4 cases of cystic renal cell carcinoma (RCC), one of simple cystic type (case 2) and three of multilocular cystic type (case 1, 3 and 4). All cases were diagnosed preoperatively as malignant neoplasms on the basis of radiological examinations, including CT scan and angiography. Pathological examination revealed that intrinsic cystic growth was the probable cause in the three cases of multilocular cystic RCC, while the simple cystic case was probably caused by secondary cyst formation as a result of tumor necrosis. Radical nephrectomy was performed in cases 1, 2 and 4 and partial nephrectomy in case 3. We recommend nephron-sparing surgery as an option in the management of select cystic RCC, given that many cystic RCCs are low grade and enveloped by distinct pseudocapsules with fibrous tissues.