Evaluation of the Paris System in atypical urinary cytology.

OBJECTIVE: Our aim was to evaluate the Paris System for reporting urinary cytology, especially in the field of atypia.

METHODS: During the last year, 104 urinary cases had atypical cytology. These cases were reviewed and reclassified by three cytopathologists using the Paris criteria. Cyto-histological correlation was performed in 47 cases. Additionally, all cytology diagnoses were correlated with double immunocytochemistry for p53 and CK20 result. Interobserver consistency was also evaluated.

RESULTS: Out of 104 atypical cases, 30 were classified as benign, 49 atypical and 25 suspicious for high-grade urothelial carcinoma (HGUC). Diagnostic consistency between the three observers reached 93.27%. Using the new criteria, only 47.1% of the cases remained in the atypical category. The rate of HGUC histology was 14.3%, 26.7% and 96% in the benign, atypical and suspicious for HGUC cytological categories, respectively. Immunocytochemistry positivity was observed in 25.9%, 41.8% and 80% of the cases in the three diagnostic groups.

CONCLUSIONS: The Paris System for reporting urinary cytology provides clear, easy to adopt criteria, which lead to diagnostic categories with clinical significance, facilitating patient management decisions.