Natural history of urothelial dysplasia of the bladder.

Urothelial dysplasia is the putative precursor of urothelial carcinoma in situ (CIS) and invasive urothelial carcinoma of the urinary tract. Urothelial dysplasia is frequently identified in patients with urothelial CIS and cancer. However, very little is known about the clinical presentation and natural history of urothelial dysplasia in the absence of urothelial CIS or invasive cancer. The authors studied 36 patients with isolated urothelial dysplasia at the Mayo Clinic between 1969 and 1984. None of these patients had previous or concurrent urothelial CIS or invasive cancer, and none received treatment for dysplasia. The histopathologic features of urothelial dysplasia were examined, and long-term clinical follow-up was obtained. Progression was defined as the development of urothelial CIS or carcinoma. The male-to-female ratio was 2.6:1, and the mean patient age at the time of diagnosis was 60 years (range 25-79). Urothelial dysplasia has a predilection for the posterior wall. Eleven patients had urinary irritative symptoms, 10 had hematuria, 3 had both irritative symptoms and hematuria, and 12 were found to have dysplasia incidentally. The mean follow-up was 8.2 years (range 0.1-25.5). Seven (19%) of 36 patients developed biopsy-proven progression, including 4 with CIS and 3 with invasive cancer, and 1 of them died of bladder cancer. The intervals from diagnosis to progression ranged from 6 months to 8 years (mean 2.5 years). One of the remaining 29 patients had positive cytologic results 2.5 years after the initial diagnosis of dysplasia. The authors conclude that urothelial dysplasia is a significant risk for the development of CIS and invasive urothelial carcinoma, and patients with urothelial dysplasia should be followed up closely.