Urine cytopathology is a cost-effective method to diagnose and follow patients with high grade urothelial carcinoma (HGUC). However, some benign, reactive and metaplastic changes may mimic HGUC and pose a diagnostic challenge for cytopathologists. Summary: Our comprehensive review focuses on summarizing common pitfalls encountered in urine cytopathology, based largely on the experience of the senior author (AC) utilising the diagnostic criteria described in the 2nd edition of The Paris system (TPS) for reporting urinary tract cytopathology and in recent published literature. These include urothelial tissue fragments, instrumented samples, degenerative changes, treatment effects, viral cytopathic changes, iatrogenic and metaplastic changes. Our aim is to provide a clear understanding of these challenges to assist cytopathologists in making accurate diagnoses. Key Message: It's crucial for cytopathologists to recognize benign, reactive and metaplastic lesions that could resemble HGUC. Awareness of these cytological features is essential to minimise diagnostic errors.
S. Karger AG, Basel.