Accuracy of Urine Cytology and the Significance of an Atypical Category

Fadi Brimo, Robin T. Vollmer, Bruce Case, Armen Aprikian, Wassim Kassouf, Manon Auger
2009 American Journal of Clinical Pathology  
A b s t r a c t The "atypical urothelial cell" cytologic category is nonstandardized. We subclassify atypical cases to "atypical, favor a reactive process" or "atypical, unclear if reactive or neoplastic." We evaluated the predictive significance of atypical cases by looking at their histologic follow-up. Among the 1,114 patients and 3,261 specimens included, 282 specimens had histologic follow-up. An atypical diagnosis did not carry a significant increased risk of urothelial neoplasia compared
more » ... neoplasia compared with the benign category. Although an "atypical unclear" diagnosis carried a higher rate of detection of high-grade cancer on follow-up biopsy in comparison with "atypical reactive" or "negative" diagnoses (26/58 [45%] vs 15/52 [29%] and 16/103 [15.5%], respectively), this difference was not statistically significant. These results suggest that dividing atypical cases into 2 categories based on the level of cytologic suspicion of cancer does not add clinically relevant information within the atypical category. They also raise the question of the significance of the atypical category altogether. Urine cytology is an essential modality for the detection of urothelial neoplasia. It has various indications that generally fall in 2 principal groups: in the evaluation of patients with genitourinary symptoms, especially hematuria, and as a surveillance tool for patients with a history of bladder cancer. The accuracy of urine cytology depends on several factors that are mainly related to tumor grade, the nature of specimen, and sampling. It has long been known that urine cytology is accurate in the diagnosis of high-grade urothelial carcinoma (HGUCA) with cytohistologic correlation reported as high as 98%. 1 In contrast, it carries a much lower diagnostic yield for low-grade urothelial neoplastic lesions that include papillary neoplasm of low malignant potential (PUNLMP) and low-grade papillary urothelial carcinoma (LGUCA), with sensitivity and specificity values as low as 8.5% and 50%, respectively. 2 Moreover, the specimen type also seems to impact the predictive value of urine cytology, with voided specimens being more specific and slightly less sensitive than instrumented specimens in 1 study. 2 This higher degree of specificity could be explained in part by the absence of the instrumentation-induced reactive changes with the resulting cell clustering, making the interpretation of the cytologic findings in voided urine more straightforward. Finally, several studies have shown that the number of samples increases the sensitivity of urine cytology, especially in the detection of high-grade lesions. [3] [4] [5] [6] Despite the fact that the usefulness of urine cytology was described more than 60 years ago by Papanicolaou and Marshall, 7 a major limitation of urine cytology, in contrast with the Bethesda System for reporting cervicovaginal cytology, is the lack of consensus regarding the terminology and
doi:10.1309/ajcpprzlg9kt9axl pmid:19846822 fatcat:gtdspfohlja7vo266z5hvlp5lm