Outcome of surgery in cystic renal cell carcinoma

OBJECTIVES: To review cases of cystic renal cell carcinoma treated surgically at our institution and define their clinical and histopathologic features. METHODS: Between 1986 and 1998, 21 patients with cystic renal cell carcinoma were treated surgically. Cystic renal cell carcinoma was categorized using Hartman's classification. RESULTS: Histopathologic examination demonstrated cystic necrosis in 11 patients, multilocular cystic renal cell carcinoma in 9, and unilocular cystic renal cell carcinoma in 1 patient. Tumors were incidentally found during an evaluation of unrelated disease or a general health checkup in 14 patients (67%). The mean tumor size was 5.6 cm (range 0.5 to 12) for cystic necrosis and 5.4 cm (range 2 to 9) for multilocular cystic renal cell carcinoma. All 9 cases of multilocular cystic renal cell carcinoma were of the clear cell type and tumor grade 1. The mean follow-up period was 65 months (range 9 to 141). The 5-year disease-specific survival rates for multilocular cystic renal cell carcinoma and cystic necrosis were 100% and 80%, respectively. CONCLUSIONS: The prognosis for patients with cystic renal cell carcinoma is better than that for patients with solid tumors. In particular, the prognosis of multilocular cystic renal cell carcinoma is excellent. Multilocular cystic renal cell carcinoma represents a distinct subtype of renal cell carcinoma that can be completely cured by surgery.