Urine cytology

Urine cytology plays a key role in bladder cancer screening, diagnosis, and surveillance. Although it has a high specificity of diagnosing high-grade urothelial carcinoma, the sensitivity of urine cytology is low, especially for low-grade lesions. Benign reactive changes can complicate cytology interpretation with diagnostic pitfalls. Urine cytology should be practiced in the context of patient history, and non-urothelial primary and bladder involvement of secondary tumors should be differentiated. Ancillary testing is important to the urine cytology diagnosis. This chapter will review urine cytology indications, diagnostic categories, The Paris System of reporting, and ancillary testing, as well as discuss diagnostic challenges and pitfalls.