Clinical significance of denuded urothelium in bladder biopsy

Purpose: Although to our knowledge the significance of denuded urothelium i n bladder biopsies has not been studied previously, it is thought to be a p roblem because benign urothelial cells are cohesive and not expected to she d into the urine. We correlated the pertinent clinical features of patients with denuded bladder biopsies and/or specific pathological features of den uded bladder biopsy specimens with patient outcome in regard to bladder les ions to help predict the subsequent likelihood of diagnosing bladder carcin oma in a patient with a nondiagnostic denuded biopsy. Materials and Methods: We studied 51 denuded bladder biopsies from 44 patie nts in which the average extent of epithelial denudation was 90%. Results: Of the 27 male (69%) and 17 female (31%) patients 22 to 86 years o ld (mean age 62) 34% had no history of bladder neoplasms. In remainder ther e were flat carcinoma in situ with or without other tumors (26%), high (20% ) and low (14%) grade papillary tumors without carcinoma in situ and miscel laneous conditions (6%). Overall 31% of patients were diagnosed with carcin oma in situ within 24 months (median 5.5) after the denuded specimen was ob tained. Parameters that did not correlate with the subsequent diagnosis of carcinoma in situ included cystoscopic impression, history of intravesical chemotherapy, sex, age, tissue inflammation, percent of tissue fragments wi th any denudation, number of denuded tissue fragments and percent of overal l denuded epithelium. A history of carcinoma in situ before denuded biopsy predicted a diagnosis of carcinoma in situ within 24 months after denuded b iopsy in 54% of patients in contrast to 19% of those without a history of c arcinoma in situ (p = 0.03). Factoring in a history of other bladder tumor types in various combinations did not predict carcinoma in situ after denud ed biopsy. The other predictive factor was cold cup biopsy. Carcinoma in si tu developed within 24 months in 45% of patients in whom the denuded specim en was obtained by cold cup biopsy in contrast to none who underwent hot wi re loop biopsy (p = 0.007). Cold cup biopsy and a history of carcinoma in s itu were independently predictive. Carcinoma in situ developed within 24 mo nths in 75% of patients with a history of that condition and a subsequent c old cup biopsy showing denuded epithelium. However, only 29% of those who u nderwent cold cup biopsy and had no history of carcinoma in situ were diagn osed with carcinoma in situ. Conclusions: In bladder biopsies obtained by a hot wire loop denudation mos t likely results from thermal injury when there is a low risk of subsequent carcinoma in situ. When the denuded biopsy sample was obtained by cold cup biopsy, particularly when associated with a history of carcinoma in situ, most cases represent neoplastic cell denudation and a high risk for subsequ ent carcinoma in situ.