[Histological classification of renal cell carcinoma--problems in JUA classification]

Although renal cell carcinoma (RCC) is often heterogeneous, the histological classification of RCC in Japanese Urological Association (JUA) is designed to select only the dominant histological components. We evaluated whether this system could provide an adequate information concerning the prognosis of the patients.

Histological slides of 130 cases with RCC were microscopically evaluated. We classified these cases according to the JUA classification, and also checked the presence or absence of each histological components (3 cell types and 5 histological architectures) regardless of whether or not they were dominant. Univariate and multivariate analysis were then performed to determine the histological components which have prognostic impact on patient survival.

Multivariate analysis demonstrated that only spinde/pleomorphic cells and solid architecture were the significant prognostic parameters. The presence of these histological components was not correctly shown in the JUA classification.

The histological classification of RCC in JUA did not provide enough information about the presence of the important prognostic parameters. This system should be modified to describe all the histological components regardless of whether they are dominant or not.