Outcome of atypical urothelial cells (AUC) in patients without prior history of urothelial carcinoma

Introduction

An “atypical” diagnosis is subjective in any cytologic specimen, and the interpretation is often problematic. To mitigate this issue, The Paris System for Reporting Urinary Cytology was released in 2016. Its goal was to standardize the criteria for urine cytology specimens. Atypical urothelial cells (AUC) can be a difficult diagnosis for clinicians to utilize, as it does not give a definitive answer as to whether a patient has a urothelial malignancy or not. However, a diagnosis of AUC is an acceptable option for a urine specimen that has characteristics that are clearly abnormal but fall short of malignancy.

Materials and methods

Voided urine specimens signed out as AUC in 2019 and 2020 from patients without a history of urothelial carcinoma were identified using the laboratory information system. Patient history, clinical history, and follow-up through April of 2024 were recorded. Selected cases were reviewed microscopically for the AUC diagnosis on the voided urine specimen.

Results

Of 151 cases identified, 50 (33.0%) cases included biopsy follow-up, and one case had follow-up of a ureteral brushing. Of those 51 cases, 33 (64.7%) cases had a positive follow-up, 12 (23.5%) cases had a negative follow-up, and 6 (11.8%) cases had a follow-up that showed a nonurothelial malignancy.

Conclusions

Previous similar studies have evaluated the outcome of AUC diagnoses, but it is common for those patients to have had a prior history of urothelial carcinoma. In this study, the diagnosis of AUC correlates to an eventual diagnosis of malignancy in 63.0% of cases without a known history of urothelial carcinoma. Based upon these results and previous studies, AUC appears to be a beneficial diagnosis for the patient but may lead to variable outcomes in patient follow-up.