[A report of two cases of multilocular cystic renal cell carcinoma: review of 51 cases reported and the results of a prognostic survey].

We report 2 cases of multilocular cystic renal cell carcinoma. One was in a 33-year-old male, presenting with ultrasonic abnormality of the left kidney at an annual employee health care examination. Computerized tomography (CT) demonstrated a 5 cm of multilocular cystic mass adjacent to the lower pole of the left kidney. Another was in a 44-year-old male, presenting with microscopic hematuria at an annual employee health care examination. CT of the abdomen revealed a 6.5 cm of multilocular cystic mass on the upper pole of the right kidney. Both were diagnosed as renal cell carcinoma by the angiography and underwent radical nephrectomy. Gross specimens showed typical multilocular cystic appearance and histopathology showed clear cell carcinoma infiltrating septa and replacing epithelium of the cyst walls. Both patients are alive without evidence of disease at, 21 months and 14 months after operation, respectively. Including our cases, 51 multilocular cystic renal cell carcinoma and multilocular cystic nephroma associated with renal cell carcinoma have been reported. From the review of the literatures and the answer of the questionnaires inquiring about the outcome of the patient to Japanese reporters, the outcome of 38 patients was ascertained. The 10-year survival rates and non-recurrence rate after operation calculated by the Kaphan-Meier formula were 97.3% and 90.3%, respectively. Because of the good prognosis of reported cases, we concluded that we should choose kidney-sparing surgery for the operation of multilocular cystic renal cell carcinoma.