[895] The Spectrum of Histopathological Findings in Vesical Diverticulum: Implications for Pathogenesis and Staging

Muhammad Idrees, Jennifer Kum, Alexander Riley, Liang Cheng. Indiana University, Indianapolis, IN

Background: Diverticula are saccular evaginations of urinary bladder mucosa that are encountered in all age groups with a prevalence of 1-10%. Intradiverticular neoplasms pose diagnostic and treatment challenges. The aim of this study was to document the common morphologic changes and neoplasms found in a large series of adult and pediatric vesical diverticula.
Design: Total of 176 diverticula from 137 cases of urinary bladder diverticula were identified including adult and pediatric cases. H&E stained slides were reviewed to evaluate the spectrum of neoplastic and nonneoplastic changes.
Results: A total of 176 diverticula from 137 patients were reviewed including 47 pediatric (mean age, 7.8 y) and 90 adult (mean age, 64.6 y); 92% were male. All cases had varying degrees of fibrosis and attenuation of the muscularis propria. Of the 96 nonneoplastic cases, the prominent morphologic findings included significant chronic inflammation-35, granulomatous inflammation including foreign body giant cell reaction-4, acute inflammation-7, squamous metaplasia-9, cystitis glandularis-9, and nephrogenic adenoma-1. The pediatric cases showed no malignancy. Of the 41 neoplastic cases, 29 had high-grade urothelial carcinoma (HGUC), 3 carcinoma in situ, 5 low-grade papillary urothelial carcinoma, 2 primary squamous cell carcinoma, 1 secondary melanoma, and 1 urothelial dysplasia. Two of the HGUC had neuroendocrine differentiation. Diverticulae from 19 cases were involved by primary tumors, of which 9 had coexisting intravesical neoplasia. In 14 of 29 HGUC, infiltration into adjacent fat was noted. Six of these cases arose within diverticula. Ten cystoprostatectomy cases had associated incidental prostatic carcinoma. The commonest presenting symptoms in neoplastic cases were hematuria followed by urinary retention.
Conclusions: Diverticulum of the urinary bladder is a relatively common clinical disorder in children and adults. Fibrosis, inflammation, and urothelial metaplastic changes are frequently encountered. In addition, specimens may harbor neoplasms, most commonly urothelial carcinoma. Hypothetically, attenuation of the muscle layer associated with diverticulum formation may facilitate tumor invasion into peridiverticular soft tissues. However, we could no clearly establish that muscle attenuation in bladder diverticula has statistically significant relationship with higher tumor stage.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 147, Wednesday Afternoon

 

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