[Ultrastructure of the basic cell types of human transitional cell bladder cancer].

Electron microscopic examinations of 33 transitional cell carcinomas of the human urinary bladder demonstrated that tumor cells may retain some organ- and tissue-specific features which could be of differential diagnostic importance and indicate the degree of ultrastructural differentiation of this organ tumors. The main parenchymatous elements of transitional carcinoma include superficial (apical location of mitochondria, microvilli on the luminal surface, zones of adhesion, locking), intermediate (elongated shape, few organoids, digital processes, distended intercellular spaces, intercellular bridges), basal (large nucleus, meager cytoplasm), squamous epithelial (tonofibrils, keratohyalin, keratosomes, desmosomes) cells. Tissue-specific ultrastructural features of these tumors consist in specialized contacts (desmosomes, zones of locking and adherence), microvilli, fragments of basal membrane. Ratios of ultrastructural types of tumor cells in transitional cell carcinomas of the urinary bladder vary considerably.