[846] Urinary Bladder Sinuses. A New Pathological Finding with Clinical and Pathological Significance.

Thamara Jayasinghe, Bojana Djordjevic, Eric C Belanger, Susan J Robertson, Bich N Nguyen, Kien T Mai. The University of Ottawa, ON, Canada

Background: We studied the changes in the urinary bladder in radical cystectomy specimens characterized by segmental mucosal invaginations into the submucosa and muscularis propria. We termed these lesions as urinary bladder sinuses (UBS).
Design: 50 consecutive radical cystectomy specimens (49 for carcinoma with history of BCG/radiation/chemotherapy and 1 for neurogenic bladder) and 20 transurethral resections of the bladder (TURBT) specimens were reviewed. UBS were classified into the superficial and deep types. Superfical UBS was defined as invaginations of the mucosa (including the urothelium, the lamina propria and the muscularis mucosa) extending into the submucosa, while deep UBS was defined as mucosal invaginations extending into the muscularis propria.

Results: Superficial UBS were distinguished from cystitis cystica due to the cleft-like structures and deep UBS distinguished from the intramural ureters by the multiple cleft-like structures. UBS were often associated with cystitis cystica and proliferation of Von Brunn's nests. In TURBT specimens, superficial UBS were identified in 3 out of 20 cases. In radical cystectomy specimens, superficial UBS were identified in 35 cases (including one neurogenic bladder), while deep UBS (all with associated superficial UBS) were seen in 4 cases. Superficial UBS were more often seen at the borders of scars or outside the invasive carcinoma and were often identified at the base of the bladder. All deep UBS were identified in areas without invasive carcinoma. Intraepithelial neoplasia was seen involving the mucosa of the superficial sinuses in 2 of 4 radical cystectomy specimens and in 1 of 3 TURBT specimens. Furthermore, deep UBS were often associated with increased thickness of the muscularis propria.
Conclusions: UBS may pose diagnostic problems with deeply invasive carcinoma, as they may mimic muscle invasive cancer on pelvic examination and imaging techniques. Recognition of this type of lesion is important, both pathologically and clinically, to avoid over-staging of the tumor.
Category: Genitourinary (including renal tumors)

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 199, Tuesday Morning


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