[Prognostication of the clinical course of transitional cell papilloma of the bladder].

The dominance of nondifferentiated cells in tumor and the evidence of an early signs of metaplasia, the basal compartment disorder, accumulation in cytoplasm of tumoral cells of fibrillar protein (tonofilaments, tonofibrils), the increase of so-called "dark cells" quantity, determined as a result of ultrastructural investigation of 48 transition-cell papillomas, constitute the unfavourable prognostic factor for this disease.