[Characteristics of early carcinomas and precancerous lesions in the urinary bladder]

Early transitional cell carcinomas of the urinary bladder are morphologically classified into papillary and non-papillary types, carcinoma in situ (CIS). Severe dysplasia is considered as a precancerous lesion for CIS which can be distinguished from the morphological appearance of its AgNORs. The conversion from severe dysplasia to CIS appears to require a longer time than that needed for invasive lesion to develop from CIS. It is postulated that mild or moderate dysplasia results in G1 and 2 grade papillary transitional cell carcinomas. Molecular analysis of different types of dysplasia is therefore clearly warranted to assist in diagnostic classification.