Histopathologic and clinical features of vesical diverticula.

OBJECTIVE: To study the histopathology changes and clinical features of vesical diverticula, focusing on the neoplastic entities.
MATERIALS AND METHODS: We retrieved data for 108 patients with vesical diverticula from the archives of our institute during the past 15 years (1998 to 2012) and reviewed their clinical and pathologic characteristics.
RESULTS: Diverticula most often involved the lateral wall, followed by the posterolateral and posterior walls of the urinary bladder. Nonneoplastic processes were found in 70 of 108 patients (65%), including inflammation, metaplasia, and urothelial hyperplasia, with or without atypia/dysplasia. Primary carcinomas arising within the diverticula were found in 36 patients (33.3%), of which 33 were urothelial carcinoma, including 5 with divergent differentiation, 2 with squamous carcinoma, and 1 with adenocarcinoma. Patient follow-up for neoplastic diverticula (mean, 59 months; range, 1-108 months) showed that no patients died of disease progression. Concurrent or subsequent urothelial carcinoma was present in the nondiverticular bladder in 19 of 36 patients (53%). Four patients with subsequent extradiverticular urothelial carcinoma showed progression, with pathology upstaging.
CONCLUSION: Inflammation, metaplasia, and dysplasia are commonly seen in vesical diverticula. In our series, which includes patients who underwent endoscopic or surgical intervention and microscopic examination, those with vesical diverticula appeared to have a significantly higher risk for development of urothelial carcinoma, which can occur synchronously or precede carcinoma of the nondiverticular bladder. Compared with their non-diverticulum-associated counterparts, a significantly higher percentage of diverticulum-associated bladder carcinomas are high-grade and invasive. Conservative approaches are suggested for tumors confined within diverticula, after extensive investigation of the nondiverticular bladder.