Multilocular cystic renal cell carcinoma: an experience of clinical management for 31 cases.

In order to increase our knowledge and understanding about multilocular cystic renal cell carcinoma (MCRCC), including diagnosis, surgical management, pathologic and prognostic characteristics, clinical data of patients who suffered with MCRCC were reviewed retrospectively. From 1998 to 2005, among 770 patients diagnosed with renal cell carcinoma (RCC) at our institute, 31 cases (4.0%) were identified as MCRCC. The average age of patients suffered with RCC and MCRCC was 58.1 +/- 3.6 and 45.9 +/- 2.7, respectively (P < 0.01), whereas the gender ratio of male to female in RCC and MCRCC is 2.12:1 and 2.88:1(P < 0.01). Surprisingly, 28 of those 31 renal masses (90.3%) were first discovered on the radiographic image, and the size of tumors in maximum diameter ranged from 1.7 to 11.0 cm (mean 4.1 +/- 2.2 cm). All those patients were treated with open nephrectomy, including 21 radical and 10 partial. The stages of tumor were classified as pT1N0M0, pT2N0M0, and pT3bN0M0 following the 1997 criteria of tumor-node-metastasis (TNM) classification in the number of 27(87.1%), 3(9.7%) and 1(3.2%), respectively. By contrast, according to the tumor nuclear grading system, those tumors were classified as Grades 1 and 2 in 13 (42%) and 18 patients (58%), respectively. Only 29 cases from those patients have been followedup for a period of 9 to 81 months so far (mean 32.6 +/- 11), while no tumor recurrence occurred except for 1 case who died of causes other than MCRCC. In general, MCRCC is a frequent subtype of RCC in the clinic. A nephron-sparing procedure should be considered in the preoperative plan when a complex multicystic renal mass with enhanced density is observed.