SUMMARY PECULIARITIES OF ULTRASTRUCTURE OF RENAL INTRATUBULAR NEOPLASIA ZONES AT CLEAR CELL RENAL CELL CARCINOMA

Abstract

The aim was to investigate in a comparative plan the ultrastructural peculiarities of cells, cellular and noncellular elements of renal intratubular neoplasia of peritumoral tissue with highly, average and low grades of differentiation at clear cell renal cell carcinoma (CCRCC). Material and methods. Material for conducting transmission electron microscopic researches was postoperative biopsies of the peritumoral tissue at highly differentiated CCRCC (G1) – five cases; at an average grade of differentiation (G2) – five cases; at low grade of differentiation (G3) – six cases. The renal tubules (RT) and tangential stroma elements with different differentiation (G1, G2, G3) in peritumoral tissue at the ultrastructural level were investigated. Results. It was revealed that in RT of peritumoral tissue at highly differentiated CCRCC (G1) and the average degree of differentiation (G2) cells of renal intratubular neoplasia zones are represented mainly in the average electronic density by little-differentiated epithelial cells with a large nuclear-cytoplasmic ration. Epithelial cells with small nuclear-cytoplasmic ratio, the cytoplasm of which is filled with disorganized small mitochondria, Mallory bodies, glycogen granules and autophagosomes, are present in separate cells zones of the renal intratubular neoplasia with the CCRCC of the indicated degrees of differentiation. Peritumoral tissue at highly differentiated CCRCC (G1) and the average degree of differentiation (G2) contains hemocapillaries, small venules, clusters of fibroblasts, macrophages, plasmocytes. A characteristic ultrastructural feature of peritumoral tissue with a low degree of differentiation (G3) at CCRCC is the presence of a small diameter RT coated with very thick and simultaneously flaky basal membranes. Typical for separate small differentiated epithelial cells of renal intratubular neoplasia zones RT of peritumoral tissue at CCRCC of low degree of differentiation (G3) is the presence in their cytoplasm of a very large size, spherical form of Mallory body with the electron-density, connected with the outer membrane of the nuclear shell. It was also revealed that in the conditions of renal intratubular neoplasia, a number of zones of renal intratubular neoplasia RT of peritumoral tissue are filled with epithelial cells, the cytoplasm of which contains a giant size of the autophagosome and electron-density cluster of glycogen granules. The autophagosome contains small lipid drops of insignificant electron density and approximately the same size of a very high electron density spherical formation of unspecified nature. Conclusions. Epithelial cells of the renal intratubular neoplasia zones of peritumoral tissue at CCRCC of low degree of differentiation (G3), in the comparative plan with similar epithelial cells of the renal intratubular neoplasia zones of peritumoral tissue with high (G1) and the average (G2) degrees of differentiation, have cytoplasm, which is the most saturated Mallory bodies, autophagosomes, electron-density clusters of granules of glycogen.

Keywords

• clear cell renal cell carcinoma, peritumoral tissue, renal intratubular neoplasia, ultrastructure