Bladder histological changes associated with chronic indwelling urinary catheter

Purpose: Chronic urinary catheters induce histological changes in the bladd er with time. The exact etiology of these changes is postulated to arise fr om inflammation and local tissue response. We elucidate the incidence of no nmalignant histological change in bladder biopsies of patients with chronic indwelling urinary catheters. Materials and Methods: During 7 years 208 spinal cord injured patients unde rwent bladder biopsies as part of a surveillance program for vesical malign ancy. All patients had chronic (more than 8.5 years) indwelling urethral or suprapubic catheters as definitive management for neurogenic voiding dysfu nction. Biopsies were obtained from 4 to 6 sites within the bladder includi ng areas that were visually abnormal. All samples were routinely fixed with hematoxylin and eosin staining, and interpreted by an experienced patholog ist. Results: A total of 17 patients were identified with malignancy, including 10 with squamous cell carcinoma, 5 with transitional. cell carcinoma and 2 with adenocarcinoma. Nonmalignant changes occurred in 48 patients (23%) wit h keratinizing squamous metaplasia or cystitis glandularis, each of which i s considered a premalignant lesion. Conclusions: To our knowledge our study represents the largest group of spi nal cord injured patients to undergo biopsy evaluation after chronic cathet er use. A spectrum of inflammatory and proliferative pathological. conditio ns were identified, which were predominantly inflammatory and squamous. The need to survey ongoing transitional mucosal. changes in this population is underscored by the spectrum of histological abnormalities and the signific ant occurrence of malignant pathologies in our patients.