NCIt definition : A non-invasive papillary urothelial carcinoma characterized by minimal cytologic atypia
and infrequent mitotic figures (usually limited to the lower half of the tumor). It
usually occurs in the urinary bladder, but it can arise from other sites in the urinary
tract. This type of carcinoma recurs frequently, may invade the urinary tract wall,
and has a low risk of progression.;