Clinical, histopathological and flow-cytometric properties of incidental renal cell carcinomas

Medical records of 63 patients operated on for renal cell carcinoma (RCC) between 1986 and 1996 in the Karlovac General Hospital were studied retrospectively. In 23 (36.5%) patients, the tumor was incidentally detected. The median patient age was 62 in the incidental group and 64 years in the symptomatic group (P > 0.05). Ultrasonography was the leading technique for incidental detection of RCC. The median tumor diameter was 6 cm in the incidental group and 9 cm in the symptomatic group (P < 0.001). Incidental carcinomas had a lower stage (P = 0.022) and a lower nuclear grade (P < 0.001) than the symptomatic ones. The incidental cases were associated with a more favorable ploidy status (P = 0.027) and a lower proliferative activity (P = 0.005). The 5-year survival rate was significantly higher in incidental (81.4%) than in symptomatic cases (44.3%) (P = 0.020). Univariate analysis showed that tumor stage, ploidy status, and proliferative activity were good prognostic parameters, while patient age, tumor size, and nuclear grade were not. Tumor stage was the only independent prognostic parameter in multivariate analysis. In conclusion, the incidentally detected RCC show more favorable clinical, histopathological, and flow-cytometric characteristics and their prognosis is significantly better than in symptomatic cases.