Does polyomavirus infection interfere with bladder cancer fluorescence in situ hybridization?

Polyomavirus (BK) cytopathic effect in urine cytology is not associated with high risk of developing high-grade urothelial carcinoma

INTRODUCTION

Polyomavirus cytopathic effect (BK-CPE) is classified as "negative for high-grade urothelial carcinoma" (NHGUC) in the Paris System for Reporting Urinary Cytology. However, polyomaviruses have been historically associated with tumor development and have been recently reported as an independent risk factor for renourinary carcinoma in transplant patients. The aim of the present study was to investigate the relationship between polyomavirus infection in the urinary tract and the subsequent risk of developing high-grade urothelial carcinoma (HGUC) in the general population.

MATERIALS AND METHODS

A retrospective case-control study was conducted to assess BK-CPE in all urinary cytology examinations performed from 2009 to 2011 for cases with an interpretation of NHGUC, NHGUC with BK, atypical urothelial cells (AUCs), or AUCs with BK. The endpoint of the present study was a diagnosis of HGUC on either bladder biopsy or urine cytology for those patients with subsequent follow-up data.

RESULTS

A total of 252 cases with a urinary cytology interpretation of NHGUC, 234 with NHGUC + BK, 255 with AUCs, and 64 with AUCs + BK were identified. The surgical and cytological follow-up data showed that the overall risk of the development of HGUC for those with NHGUC, NHGUC + BK, AUCs, and AUCs + BK was 6.0%, 6.8%, 23.5%, and 12.5%, respectively. No statistically significant differences were found between the patients with NHGUC and those with NHGUC + BK. A statistically significant difference was found for patients with AUCs compared with patients with NHGUC + BK and those with AUCs + BK (P < 0.001).

CONCLUSIONS

The presence of BK-CPE in urine cytology samples does not increase the overall risk of the development of HGUC. Our results support the recommendation from the Paris System for Reporting Urinary Cytology to place urine samples with BK-CPE in the NHGUC category.

What should not be reported as atypia in urine cytology

The term "atypia," although not well characterized, is widely used in diagnostic surgical and cytopathology. Because there are no guidelines regarding when to use this term, in the majority of cases, it is used as a "wastebasket." This definitely applies to urine cytology, where the reported rate of atypia ranges from 1.9% to 23%. This review lists a number of cytomorphologic findings in urine cytology that are associated with known and specific causes. Urine specimens in which the morphologic changes can be attributed to particular etiologic factors should no longer be classified as "atypical." These include urine specimens showing reactive umbrella cells or seminal vesicle cells, reactive changes due to stones, cytologic changes characteristic of infectious processes or therapy effect, instrumented urines with pseudopapillary clusters, and urinary diversion specimens.