[Carcinoma and oncocytoma of the kidney. Phenotypic characteristics and prognostic features].

Abstract

The present investigation is based on the morphological analysis of 1224 renal cell carcinomas and 68 renal oncocytomas from the kidney tumor registry of the Institute of Pathology, University of Mainz. The subclassification of epithelial renal cell tumors in 5 basic types (i.e. clear cell type, chromophilic type, chromophobic type, oncocytic type and duct Bellini type) as proposed by Thoenes and coworkers (1986) was taken as the basis for a systematical study. It refers especially to ultrastructural aspects and antigen profiles of the tumor cells established immunohistologically in relation to the nephron/collecting duct epithelia. Thus, the study focuses on problems of phenotypia and histogenesis. Finally, morphological parameters of prognosis in renal cell carcinomas are taken into account as well. I. Ultrastructural analysis provides further knowledge of the morphological differences between the various basic cell types of epithelial renal tumors. Structural similarities are presented between the basic cell types of clear cell and chromophilic renal cell carcinomas and cells of the proximal tubules, on the one hand, and the basic cell types of the chromophobic renal cell carcinomas, duct Bellini carcinomas as well as oncocytomas and cells of the collecting duct, on the other hand. This can sometimes be traced back to the single cell level (chromophobic renal cell carcinomas: intercalated cell type B). The results of the freeze fracture analysis confirm this view and, for the first time, morphologically prove molecular anomalies of the oncocytic mitochondria membrane. Initial tumor development can be observed for the chromophilic renal cell carcinoma, the duct Bellini carcinoma, as well as the renal oncocytoma and chromophobic renal cell carcinoma. This development demonstrates the relationship these tumor types have to well-defined segments of the nephron/collecting duct (i.e. proximal tubule, medullary and cortical collecting duct). II. The immunohistological analysis demonstrates characteristic antigen profiles of every renal tubule segment and of every epithelial renal tumor type which can be used for differential diagnosis purposes. Two tumor groups with different morphological phenotypes can be identified. The first group (clear cell and chromophilic renal cell carcinomas) mostly presents antigens of the proximal tubule, while the second group (chromophobic renal cell carcinomas, duct Bellini carcinomas, oncocytomas) mostly expresses antigens of the collecting duct. In the case of the renal oncocytomas, for example, the expression of the band 3 antigen exhibits a relationship to the single cell level (i.e. the intercalated cells type A).(ABSTRACT TRUNCATED AT 400 WORDS)