Bladder
Acquired non-neoplastic anomalies
Diverticula

Author: Alcides Chaux, M.D. (see Authors page)

Revised: 15 March 2016, last major update July 2011

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Bladder diverticula
Definition / General
  • Outpouchings of urothelial mucosa through bladder muscular wall
Epidemiology
Sites
  • Most diverticula are solitary lesions located in lateral walls of bladder
Etiology
  • Congenital cases are due to bladder outlet obstruction or failure of muscle development (eMedicine)
  • Acquired cases are more common, and usually due to prostatic enlargement causing muscular hypertrophy and focal mucosal herniation without muscularis propria in areas of weakness, often near ureteral orifices, bladder dome or urethral orifice
Clinical Features
  • Most bladder diverticula are small and asymptomatic
  • When symptomatic, usually associated with infections and stones (due to urine stasis), urinary retention or perforation
  • Some cases are associated with additional GU anomalies (urethral strictures, neurogenic bladder, duplicated collecting system) or hereditable syndromes (Ehlers-Danlos, others)
  • Malignancy occurs in 1-10% of bladder diverticula
  • Tumors are often large because location is hidden
  • All variants of urothelial carcinoma have been reported in bladder diverticula, with a relatively higher frequency of unusual subtypes when compared to the general population
Case Reports
Treatment
  • Varies by patient - nonoperative treatment, surgical bladder outlet reduction or removal of the diverticulum
Gross Description
  • Narrow necks, round/ovoid pouch from 1-18 cm (average 5.0 cm)
Gross Images

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Image with case history

Diverticulum containing sarcomatoid carcinoma

Micro Description

Nonneoplastic findings
  • Wall consists of fibrous tissue with no/scant muscularis propria
  • Common findings include inflammation, granulation tissue formation, erosion, cystitis cystica et glandularis, nonkeratinizing squamous metaplasia, reactive urothelial atypia


Neoplastic findings
  • Most neoplastic lesions that arise in bladder diverticula are urothelial carcinomas, mainly noninvasive papillary (high/low grade) or invasive
Micro Images

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Histologic features


Subtypes of invasive bladder cancer arising in bladder diverticula


Diverticulum containing sarcomatoid carcinoma