Urinary tract washing specimens containing atypical urothelial tissue fragments are significantly associated with urothelial neoplasia

Background: We previously found that the presence of atypical urothelial tissue fragments (AUTF) was associated with an increased risk of high-grade urothelial carcinoma (HGUC) but not low-grade urothelial neoplasia (LGUN) in voided urine (VU) specimens. However, we subsequently found that patients with LGUN were more likely to have cytologic atypia in urinary washing (UW) specimens, suggesting that cytologic atypia found in UW specimens might be associated with both LGUN and HGUC. In this study, we retrospectively examined UW specimens containing AUTF to determine whether they were associated with HGUC, LGUN, or both HGUC and LGUN. Methods: 1173 UW specimens and any follow up biopsies were identified over a 10-year period and the presence of AUTF was recorded based on the original clinical diagnosis. Results: The presence of AUTF in UW specimens was significantly associated with high-risk indeterminate diagnosis or definitive diagnosis of HGUC (P <.001). In addition, AUTF specimens were significantly associated with a neoplastic diagnosis of low-grade urothelial carcinoma (LGUC) or HGUC on subsequent biopsies when compared to specimens lacking AUTF (P =.047). The overall rate of CIS/HGUC in specimens with AUTF was 33.0 vs. 13.5% for specimens without AUTF (P =.051). Conclusions: Urothelial tissue fragments (UTF) found in UW specimens should be examined for the presence of cytomorphological atypia, as the presence of AUTF almost triples the risk of HGUC. As opposed to what has been found in VU specimens, AUTF in UW specimens is also associated with an increased risk of LGUN.