Histopathologic features and clinical outcomes in 71 cases of bladder diverticula.

CONTEXT: Bladder diverticula often come to clinical attention when complications or malignancy occur, although limited information is available regarding histopathologic features and clinical outcomes.
OBJECTIVE: To identify the morphologic findings, neoplastic subtypes, and clinical outcomes by reviewing all bladder diverticula that underwent pathologic sampling for primary diverticular processes at the Cleveland Clinic.
DESIGN: Hematoxylin-eosin slides from 71 cases of bladder diverticula were reviewed. Clinicopathologic features and patient outcomes were obtained from a retrospective review of patient records.
RESULTS: Patient ages ranged from 1 to 81 years (mean, 55 years), and the ratio of males to females was 68:3. Diverticular size ranged from 1 to 18 cm (mean, 5.3 cm) and often involved the lateral walls (38/71; 54%). Neoplastic changes were present in half of cases (36/71; 51%), including both noninvasive (16/36; 44%) and invasive (20/ 36; 56%) carcinoma. Of the invasive carcinomas, less-common subtypes included small cell carcinoma (n = 3), squamous cell carcinoma (n = 2), and adenocarcinoma (n = 1); 9 cases were pT1 (45%) and 11 cases were pT3 (55%). Follow-up for patients with benign findings demonstrated no subsequent neoplastic bladder disease. Patient follow-up for neoplastic diverticula (median, 27 months) demonstrated 4 cases of local recurrence and 3 cases of subsequent metastases. Of 9 patients with pT1 disease, only 1 patient (11%) developed subsequent metastases, whereas patients with pT3 disease demonstrated a higher rate of both local recurrence (3/11; 27%) and subsequent metastases (2/11; 18%).
CONCLUSIONS: Patients with invasive carcinoma in diverticula have an increased frequency of less-common bladder cancer subtypes, and those with pT3 disease are at increased risk for subsequent progression.