Urine cytopathology: challenges, pitfalls, and mimics.

Urine cytopathology is a useful and noninvasive tool in the diagnosis and follow-up of urothelial neoplasia, which remains complementary to emerging molecular tests. These specimens may be challenging and there are numerous mimics and diagnostic pitfalls with which to contend. This review discusses these various entities and includes consideration of ancillary tests that may be useful in the diagnostic procedure.