[Leukoplakia of the bladder].

The urinary bladder leukoplakia from 42 patients was studied clinico-morphologically, histochemically and electron microscopically. This precancerous condition is observed in 58,3 cases of chronic cystitis, more frequently in females. Three successive stages of the leukoplakia development under the conditions of the inflammatory process can be distinguished: squamous-cell modulation, squamous-cell metaplasia, squamous-cell metaplasia with keratinization. The formation of fissure-like intercellular bridges and the appearance of the long dense bundles of tonofibrils in the cytoplasm are the early ultrastructural signs of squamous-cell metaplasia of the transitional epithelium which are of the differential-diagnostic importance.