A bladder diverticulum is defined as an outpouching of the bladder wall devoid of a functional muscularis propria lining which results from persistent bladder outlet obstruction. This outpouching of the bladder wall easily induced inflammation, calculus, infection, and malignancy.

A 80 years old male had presented with hematuria for already half a year. He came to our outpatient department where urinalysis showed moderate hematuria. Thus, cystoscopy and TURBT was done and pathology showed urothelial carcinoma in situ, pTis. Bladder diverticulum was also found during the cystoscopy but no tumor was noted within it. 5 cycles BCG induction therapy had been finished 3 months later.

The urine cytology obtained 3 months later showed atypical urothelial cells. Intravenous pyelography was done and revealed a large bladder diverticulum at left posterior wall (Fig.1). TURBT was done and revealed a 1cm paillary tumor located inside the diverticulum edge(Fig. 2). The pathology report showed non-invasive papillary urothelial carcinoma, high grade, pTa so CTU were arranged for re-staging. The result showed a bladder enhancing nodule about 1.3 cm at left bladder diverticulum, tentative staging was Ta-1N0Mx(Fig. 3). Then he received robotic assisted laparoscopic partial cystectomy as clinical suggestion.

Intradiverticular neoplasm is hard to diagnose so alertness should be enhanced if diverticulum is noted under cystoscopy with symptom of painless hematuria.