Bladder Cancer Pathology

Many changes have been made in recent years with regard to pathological assessment of bladder cancer/urothelial carcinoma (BC/UC), and understanding of bladder carcinogenesis has evolved. This chapter describes the latest findings of the WHO (World Health Organization) 2022 classification. New approaches and developments in pathological assessment are described, emphasizing key issues, some of which lack consensus. Molecular findings play an important role in the pathological assessment of UC. With the help of this information, pathologists and clinicians have improved understanding of urothelial carcinogenesis, and this can identify the key facts to prioritize in reporting to provide optimal information to guide patient management. This chapter focuses on several issues; first, staging approaches are described and then issues of grading. This is followed by discussion of the relevance of some BC molecular subtypes in histology and a brief insight into the importance of clinical information, especially with regard to the bladder wall. The chapter concludes by discussing rare issues such as bladder diverticulum and urachus carcinomas, the role of immunohistochemistry in diagnosis, urinary cytology using the Paris system, and the ICCR (International Collaboration on Cancer Reporting) worldwide consensus reporting scheme.