[Evidence for association between renal cell carcinomas and renal cystic diseases: nationwide survey in Japan].

ABSTRACT

OBJECTIVE: A scanty evidence previously reported regarding renal cell carcinomas occurring in association with renal cystic diseases prompted us to conduct a nationwide survey in July 1991. METHODS: A total of 507 hospitals responded to the questionnaire inquiring the clinical and pathological characteristics of renal cell carcinoma associated with renal cystic diseases over the previous 2 years. RESULTS: Renal cystic diseases were identified in 223 (3.9%) of 5,721 patients with renal cell carcinoma. The patients consisted of 181 men and 42 women who had a mean age of 55.2 +/- 12.5 years (SD). The renal cystic diseases comprised simple renal cysts in 72 patients (32%), acquired cystic diseases of the kidney (ACDK) in 62 (28%), cystic renal cell carcinoma in 56 (25%), multilocular renal cysts in 20 (9%), polycystic kidney in 3 (1.3%), miscellaneous cysts in 9 (4.0%), and unspecified cysts in 1 (0.4%). Simple renal cysts were more common in older patients, while ACDK and multilocular cysts were more predominant in younger patients. They included 71 dialysis patients (32%), of whom 62 (87%) had ACDK. Renal cell carcinoma occurred bilaterally in 12 patients (17%) on dialysis. Young male patients over a longer dialysis period were more susceptible to renal cell carcinoma. Low stage tumor, papillary type and granular cell subtype were more common in those on dialysis than in those without dialysis. In consideration of the Japanese general and dialysis population, we confirmed that dialysis patients with ACDK are more susceptible to renal cell carcinoma and those with polycystic kidney are less so. CONCLUSION: Renal cystic diseases may be associated with about 4% of renal carcinoma. Young male patients over a longer dialysis period who are diagnosed to have renal cysts should be regularly and closely followed by imaging study.