The evolution of the classification of neoplasms of the urinary passages has changed greatly since Friedman and Ash published the first series AFIP fascicle on the urinary bladder in 1959. In their classification, there were four variants of urothelial neoplasia, some adenomas, adenocarcinoma, and smooth muscle and lymphoid tumors.

Today the classification continues to accrue entities based upon morphology, immunophenotype, and compelling clinical associations. The classification of renal cell carcinomas has undergone a profound transformation, with the emergence of many new entities, often with characteristic genetic alterations, with significant implications for prognosis and treatment. This comprehensive, detailed, and highly illustrated fascicle is a remarkable resource to surgical pathologists and other specialists who treat patients with tumors of these sites.