Sensitivity of urine cytology in detecting high‐grade urothelial carcinoma in patients with neoplastic urinary bladder diverticula: A major cancer center experience

Abstract Background Bladder diverticula are herniations of bladder urothelium and mucosa through the muscularis propria. The reported incidence of neoplasia arising in bladder diverticula is widely variable. The authors’ objective was to study the characteristics and sensitivity of urine cytology in these patients with emphasis on primary intradiverticular bladder cancer (IDBC). Methods A 17‐year, retrospective review of all resected bladder diverticula associated with bladder carcinoma was performed. Cases that had complete diverticular resections and preresection urine samples were included in this study. The cases were divided into either primary IDBC or primary extradiverticular bladder cancer (EDBC). Demographic data and urine cytology characteristics were recorded, and sensitivity was calculated. For IDBC, a comparison between voided and cystoscopic urines was done for cases that had both collection methods performed. Results Of 70 patients with IDBC, 47 patients had urine cytology results that were either positive for high grade‐urothelial carcinoma (HG‐UC) or suspicious for HG‐UC. The sensitivity for HG‐UC in IDBC samples was 80%, compared with 82% in EDBC samples ( p > .05). Also, 28 patients in the IDBC group had both voided and cystoscopic urine samples for comparisons; in seven patients, the voided urine sample yielded a more definitive diagnosis; in 10 patients, the cystoscopic urine sample yielded a more definitive diagnosis; and, in 11 patients, both samples were equally diagnostic ( p > .05). Conclusions The characteristics and sensitivity of urine cytology in bladder diverticula were investigated in association with neoplasia, with an emphasis on primary intradiverticular bladder cancer. The results indicated that urine cytology remains a reliable screening and diagnostic test for detecting IDBC, with sensitivity similar to that for detecting EDBC, and no significant difference was noted between voided and cystoscopic samples.