Clinical significance of incidentally detected bladder wall thickening on computed tomography

Purpose: To evaluate the clinical significance of incidentally detected bladder wall thickening (BWT) on computed tomography (CT). Methods: A retrospective analysis was performed on 34,793 cystoscopy cases between January 2004 and December 2013. Among these, patients who underwent cystoscopy for the sole indication of incidentally detected BWT on CT were selected. Patients were categorized into the diffuse or focal group depending on the extent of BWT. Suspicious lesions on cystoscopy were biopsied to confirm histologic subtype. The incidence and predictive factors of bladder malignancy were examined. Results: A total of 167 (0.5%) patients received cystoscopy for incidentally detected BWT on CT, of which 11 (6.6%) patients were diagnosed with bladder malignancy. When a suspicious lesion was identified on cystoscopy, 11 of 25 (44%) patients were found to have a bladder malignancy. Of the 15 patients with diffuse BWT, 5 (33.3%) were diagnosed with bladder malignancy, consisting of carcinoma in situ in 2 patients, high-grade carcinoma in 2 patients and muscle invasive disease in 1 patient. Of the 10 patients with focal BWT, 6 (60.0%) were diagnosed with bladder malignancy, of which 3 patients had high-grade disease. On multivariate logistic regression analysis, focal BWT [95% confidence interval (CI) 1.400–25.357, P = 0.016] and atypical cells in urine cytology (95% CI 2.631–63.446, P = 0.002) were positively associated with bladder malignancy. Conclusions: Incidentally detected BWT on CT can be suggestive of bladder malignancy. Therefore, further work-up including cystoscopy and urine cytology should be performed to assess bladder malignancy.