Cystic renal cell carcinoma is cured by resection: A study of 24 cases with long-term followup

Purpose: The true incidence and biological behavior of cystic renal cell ca rcinoma are not known. To our knowledge we present the largest series of pa tients with cystic renal cell carcinoma with long-term followup Materials and Methods: We reviewed the Mayo Clinic surgical pathology files of renal cell cancer cases with a cystic component resected from 1969 to 1 997, and arbitrarily chose 75% tumor involvement by cysts as a cutoff for i nclusion in the study. Results: We identified 24 cases of clear cell renal cell carcinoma with 75% or greater involvement by cysts comprising 0.79% of 3,047 renal cell cance r cases resected at our institution between 1969 and 1997. Mean patient age was 62.7 years (range 40 to 83). A total of 11 patients (46%) underwent ra dical nephrectomy, 4 (17%) simple nephrectomy, 3 (12%) partial nephrectomy and 6 (25%) tumor enucleation. Mean tumor involvement by cysts was 84% (ran ge 75 to 95) and in 11 cases (46%) involvement was 90% or greater. Cancer s tage was TI in 20 patients (83%), T2 in 1 (4.4%) and T3a in 4 (12.5%). Canc ers were diploid in all but 1 case. Mean followup was 77.6 months (range 8 to 428, median 51). A total of 22 patients (92%) had no evidence of cancer and 2 died of intercurrent disease. Conclusions:Our results indicate that cystic renal cell carcinoma is uncomm on and usually cured by resection, regardless of size, stage or number of c ysts. These patients may benefit from nephron sparing surgery, such as part ial nephrectomy.