Applying the Paris system for reporting urine cytology to challenging cytology cases.

Background: Implementing the Paris system for reporting urine cytology (TPS) can substantiate atypical diagnosis while improving standardization and risk stratification. This study evaluates its performance and reproducibility in challenging cases and examines whether focused education of morphological features can improve outcomes.

Methods: In our prior study, urine cytology cases diagnosed as "atypical" with surgical follow-up were used.