Clinical significance of denuded urothelium in bladder biopsy.

PURPOSE

Although to our knowledge the significance of denuded urothelium in bladder biopsies has not been studied previously, it is thought to be a problem because benign urothelial cells are cohesive and not expected to shed into the urine. We correlated the pertinent clinical features of patients with denuded bladder biopsies and/or specific pathological features of denuded bladder biopsy specimens with patient outcome in regard to bladder lesions to help predict the subsequent likelihood of diagnosing bladder carcinoma in a patient with a nondiagnostic denuded biopsy.

MATERIALS AND METHODS

We studied 51 denuded bladder biopsies from 44 patients 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 old (mean age 62) 34% had no history of bladder neoplasms. In remainder there were flat carcinoma in situ with or without other tumors (26%), high (20%) and low (14%) grade papillary tumors without carcinoma in situ and miscellaneous conditions (6%). Overall 31% of patients were diagnosed with carcinoma in situ within 24 months (median 5.5) after the denuded specimen was obtained. 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 with any denudation, number of denuded tissue fragments and percent of overall denuded epithelium. A history of carcinoma in situ before denuded biopsy predicted a diagnosis of carcinoma in situ within 24 months after denuded biopsy in 54% of patients in contrast to 19% of those without a history of carcinoma in situ (p = 0.03). Factoring in a history of other bladder tumor types in various combinations did not predict carcinoma in situ after denuded biopsy. The other predictive factor was cold cup biopsy. Carcinoma in situ developed within 24 months in 45% of patients in whom the denuded specimen was obtained by cold cup biopsy in contrast to none who underwent hot wire loop biopsy (p = 0.007). Cold cup biopsy and a history of carcinoma in situ were independently predictive. Carcinoma in situ developed within 24 months in 75% of patients with a history of that condition and a subsequent cold cup biopsy showing denuded epithelium. However, only 29% of those who underwent cold cup biopsy and had no history of carcinoma in situ were diagnosed with carcinoma in situ.

CONCLUSIONS

In bladder biopsies obtained by a hot wire loop denudation most 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 subsequent carcinoma in situ.