Atypical squamous cells of undetermined significance: audit and the impact of potential litigation. Retrospective review of 682 cases

Reproducibility of the Johns Hopkins Hospital template for urologic cytology samples

INTRODUCTION

Cytologic screening for urothelial carcinoma is fraught with low sensitivity, a high indeterminate rate, and until recently, poor standardization of terminology. The Johns Hopkins Hospital John K. Frost Cytopathology Laboratory has recently developed and published a template for reporting urine cytopathology; herein, we evaluate its interobserver reproducibility.

MATERIALS AND METHODS

Two sets of 100 cases each were deidentified; each set was reviewed by 5 of 10 observers in a randomized order at the direction of computerized data collection software that tracked observation time as well as observer classification of the atypia-no atypia, atypia (AUC-US), or atypia suggestive of high-grade urothelial carcinoma (AUC-H). Specific morphologic features were also recorded. Cases were grouped into low-, intermediate-, and high-agreement based on the number of observers who made the assessment. The findings were correlated against clinical outcomes.

RESULTS

High agreement among observers about the presence or absence of high-grade features was possible in approximately two-thirds of indeterminate urine cases. Time and order did not factor significantly into observer propensity for identifying atypical features or favoring either AUC-US or AUC-H, and cases with high agreement about the presence of high-grade features were more likely to have a malignant follow-up. Furthermore, AUC-H diagnoses based on 2 or more high-grade features had a significantly higher malignancy risk than AUC-US diagnoses did.

CONCLUSIONS

AUC-H is a valid diagnostic category with specific, reproducibly identified features that portend a higher risk of malignancy than the findings of AUC-US.