Application of The Paris System to atypical urine cytology samples: correlation with histology and UroVysion^® FISH

To evaluate whether atypical urine cytology cases may be stratified more objectively using The Paris System (TPS) and whether reclassified cases correlate with histology and UroVysion^® results.

Atypical urine cytology cases subjected to UroVysion^® testing over a period of 6 years were reviewed. Each case was reclassified according to TPS and correlated with histology and UroVysion^® results.

A total of 91 cases were identified; 70.3% were reclassified as 'negative for high-grade urothelial carcinoma (HGUC)' and 14.3% as 'atypical urothelial cells (AUC)'. The histological correlation was available in 45 cases. In the 'negative for HGUC' category, 67.9% had no histological evidence of malignancy, but 17.9% were diagnosed as HGUC. In the 'AUC' category, histology revealed urothelial carcinoma in 70% of the cases (of these, 71.4% were high grade). There was no histological evidence of malignancy in 30% of cases; notably, all of which were from patients under surveillance. The sensitivity and specificity of UroVysion^® were 85.7% and 33.3% in the 'AUC' group and 62.5% and 100% in the 'negative for HGUC' group.

The Paris System is an objective template for reporting urine cytology specimens, and is particularly useful in identifying HGUC cases and refining the category of 'AUC'.