[Clinicopathological studies and flow cytometric analysis on renal cell carcinoma after incidental finding]

Of 173 patients with renal cell carcinoma treated at the Keio University Hospital between 1979 and 1989, 48 cases were found to have their tumors incidentally (group 1), and the remaining patients presented with signs and/or symptoms related to their tumors (group 2). In this study we attempted to define the clinicopathological and ploidy characteristics of the tumors in the patients of the two groups. The number of patients having tumor stages not exceeding pT2NOMOV- was significantly higher in group 1 (81.3%) than in group 2 (36.0%) (p less than 0.001), and the median tumor size was significantly smaller in group 1 (4.32 +/- 2.38 cm) than in group 2 (7.86 +/- 4.07 cm) (p less than 0.001). The survival rate in group 1 was significantly favorable when compared with group 2 (p less than 0.005). And even in the same stage (pT1-2NOMOV-) there were statistical significance in the survival and relapse rate between the two groups (p less than 0.05), which indicate that renal cell carcinomas detected incidentally are associated with biologically low malignant potential. From 1985, flow cytometric DNA analysis was performed in 32 tumors from the group 1 and in 50 from the group 2. The frequency of occurrence of aneuploid pattern was significantly lower in tumors from the group 1 (25.0% in the overall patients and 16.0% in those with stage pT1-2NOMOV- tumors of group 1) than in those from the group 2 (52.0% in the overall patients and 42.9% in those with stage pT1-2NOMOV- tumors) (p less than 0.05). These results also suggest that renal cell carcinomas detected incidentally are associated with low malignant potential biologically.