The impact of subdividing the "atypical" category for urinary cytology on patient management

Introduction: The purpose of the study is to determine the impact of subdividing the "atypical" cytology interpretation into two groups: Atypical urothelial cells of uncertain significance (AUC-US) and Atypical urothelial cells suspicious for high-grade urothelial carcinoma (AUC-H/SHGUC), on management of patients with no prior history of UC.

Materials and method: This is a retrospective study of "atypical" urine cytology with subsequent tissue examination occurring within six months. Cytology reports with "atypical" interpretation were reclassified into AUS-UC and AUC-H based on morphologic features identified by the Johns Hopkins system and the Paris system for urine cytology. Follow-up and categorical outcomes were compared between the reclassified AUC-US and AUC-H groups.

Results: There was no significant difference (P < 0.4539) in the rate of cytology follow-up, the follow-up cytology result (P < 0.1845), or time between follow-up cytologies (P < 0.0869) between the reclassified atypical group of AUC-H and AUC-US. There was a significant association (P < 0.0001) of rate of malignancy with the reclassified AUC-H (87.18%) compared to the AUC-US (58.68%) groups.

Conclusion: There was no difference in follow-up between the AUC-H and AUC-US, however there was a difference in the rates of malignancy in the two groups. The AUC-H group is similar to the SHGUC group of the Paris system and can be considered as such, whereas the AUC-US group should continue to be considered atypical. We conclude that reclassification of the "atypical" category into AUC-US and AUC-H/SHGUC can reduce the rate of atypia and help in focused follow-up and targeted management. Diagn. Cytopathol. 2016;44:477-482. © 2016 Wiley Periodicals, Inc.