ATYPICAL CYSTS, ACQUIRED RENAL CYSTIC-DISEASE, AND RENAL-CELL TUMORS IN END STAGE DIALYSIS KIDNEYS

Abstract

Hyperplasia and tumors of epithelium are found in end stage dialysis kidneys. Epithelial hyperplasia is most conspicuous within atypical cysts in which the lining cells are multilayered and occasionally papillary. These features were studied histologically in the kidneys of 66 renal failure patients. Atypical cysts were observed in 20 of the 66 cases. Solid or cystic renal cell adenomas were found in 9 cases. Six adenomas cases were among the 20 cases with atypical cysts. Tumors occurred in kidneys having atypical cysts, as distinguished from kidneys without such cysts, with a frequency greater than would be expected to be due to chance alone (P = 0.0106). Renal cell adenomas are found at a younger age in dialysis patients (mean = 41.2 yr) than in a control group of autopsies and surgical cases (mean = 61.8 yr). These observations provide histologic evidence that renal cell neoplasms are prone to develop in relatively young renal failure patients when treated by long-term dialysis and that the stimulus for neoplastic growth accompanies a cystic transformation of the kidneys. Kidneys in 5 cases in the series, although much smaller than normal, were grossly multicystic, corresponding to the recently recognized acquired renal cystic disease. Hyperplastic cells, like those observed in atypical cysts, were present focally along the cyst walls. This form of epithelial hyperplasia, common to atypical cysts and the multicystic dialysis kidney, may give rise to the renal cell tumors that are reported to occur with increased frequency in acquired cystic disease.