[Morphology of precancerous mucosal changes in the bladder].

A morphological analysis of 346 biopsy specimens from 140 patients with chronic cystitis permits one to evaluate a nonproliferative and proliferative forms of the disease as well as the squamous-cell metaplasia (leukoplakia) of urothelium as the risk diseases in the development of bladder cancer. Among them only the cases with dysplasia foci of urothelium or the squamous-cell metaplasia with acanthosis or dysplasia from the risk group belonging to bladder precancer. The early ultrastructural signs of urothelial dysplasia are determined; among them the proliferation of the undifferentiated cells with an increased nuclear-cytoplasmic ratio, the disappearance of asymmetrical mutual membrane, vesicular apparatus and cytoplasmic polarity of the superficial cells are to be distinguished.