Paris System Has A Higher Cytohistologic Correlation And Reproducibility Than Traditional Urine Cytology Method

Abstract

Abstract Introduction/Objective The major limitation of urine cytology is the lack of consensus regarding the terminology and diagnostic criteria that should be used for urothelial atypia. The main goal of the newly proposed Paris System for Reporting Urine Cytology is to concentrate primarily on the detection of high grade urothelial carcinoma while minimizing the detection of low grade lesions. This study aimed to apply the criteria and categories of the Paris system in retrospectively collected urine cytology specimens and assess histologic correlation and reproducibility. Methods Two senior pathologists independently reviewed retrospectively collected urine cytology specimens strictly following the Paris system criteria for categorization. Cytologic diagnosis were compared with previous cytology result and histologic diagnosis. Results A total of 67 patients were included in the study. The mean age is 65.8 years (36-89 years), majority were males (73.1%) and African American (89.6%). Urine cytology using traditional method showed mostly atypical results (58.2%), followed by reactive (26.9%), high-grade urothelial carcinoma (11.9%) and suspicious (3.0%). On the other hand, the Paris system had more negative results (62.7%), followed by atypical (19.4%), high-grade urothelial carcinoma (11.9%) and lastly suspicious (6.0%). All of negative cases (18 out of 18) and majority of HGUC cases (7 out of 8) were concordant between the two cytology methods. Traditional urine cytology method only yielded 71.4% histologic concordance, while 100% Paris system results were concordant with bladder histology. Majority of the atypical cases using traditional method were converted to negative, and a few atypical cases were converted to suspicious and high-grade. All results using Paris system were concordant between two general pathologists. Conclusion Using the Paris system in analyzing urine cytology resulted to higher cytohistologic concordance than traditional method. Majority of atypical cases from traditional method were converted to more definitive categories. The cytopathologic analyses from two general pathologists applying the criteria of Paris system had superior reproducibility. Applying the Paris system, therefore, can significantly improve the performance of urine cytopathology.