A bladder diverticulum is a herniation of bladder urothelium through the muscularis propria. Because its wall lacks organized muscle, it empties poorly — predisposing to stasis, infection, stones, and (in acquired cases) malignancy.
Classification
| Feature | Congenital | Acquired |
|---|---|---|
| Mechanism | Congenital detrusor weakness | Neurogenic dysfunction or outlet obstruction (almost always) |
| Location | ~90% near the UVJ (lateral/posterior to the orifice) | Often near the UVJ; often multiple |
| Bladder wall | Smooth-walled, not trabeculated | Trabeculated, thick-walled |
| Obstruction | May occur without BOO (up to 60% have a syndrome/neuropathic cause) | In men usually >60 with BPH (~70%); in women suggests a BOO etiology |
| Malignancy risk | Virtually none | Increased (most commonly urothelial carcinoma) |
Cellules and saccules are smaller outpouchings on the same continuum. A "Hutch" diverticulum lies superolateral to the ureteral orifice without trigone involvement, in neuropathic bladder with VUR. Diverticula may deviate the ipsilateral ureter (medial deviation most common). Congenital diverticula usually present in childhood with UTI from stasis (~13% have VUR).
Diagnosis and Evaluation
- Most are found while investigating LUTS, hematuria, or infection. Finding a diverticulum in an adult should prompt evaluation for BOO plus endoscopy and lower/upper-tract imaging.
- Labs: urinalysis, culture, cytology, PSA if appropriate.
- Imaging: lower tract — CT and/or VCUG (VCUG with AP/oblique/lateral views shows anatomy, size, VUR, and emptying); upper tract — CT or renal US (up to 7% of adults have silent hydroureteronephrosis; up to 30% of children have upper-tract abnormalities). DDx of a fluid-filled peri-vesical structure (5): Müllerian cysts, gynecologic abnormalities, urachal cysts, ectopic ureter/ureterocele, postsurgical changes (lymphocele).
- Cystoscopy — inspect the entire interior for stones or abnormal epithelium; biopsy carefully (thin wall, perforation risk).
- Urodynamics — videourodynamics helps identify neurogenic dysfunction (treat before/with surgery to avoid recurrence). Contractility may appear falsely diminished from a "pressure sink" (detrusor decompresses into the diverticulum) but is actually similar to BPH without diverticula; PVR may be elevated from retained diverticular urine.
Management
Options: surveillance, surgery (endoscopic/open/laparoscopic/robotic), or catheterization.
- Surveillance — for adults with minimal symptoms and no complicating factors; counsel on the increased malignancy risk (from stasis/chronic inflammation) and the need for periodic reassessment (symptoms, cytology, endoscopy). Diverticulum size does not correlate with symptoms or complications.
- Surgery — indications (5): stones in the diverticulum, upper-tract deterioration (obstruction/reflux), persistent symptoms refractory to medical therapy, recurrent UTI, and carcinoma/premalignant change. Tumors within a diverticulum have a poor prognosis (the wall lacks muscularis propria → early transmural/extravesical spread and inaccurate staging at TUR) — an aggressive approach is advised, and invasive diverticular tumors are an indication for timely cystectomy (2015 CUA NMIBC). Manage coexisting BOO before or with the diverticulum.
- Endoscopic — TUR of the diverticular neck + fulguration of the lining, for elderly/comorbid patients or those undergoing TURP.
- Open/lap/robotic — usually a transvesical extraperitoneal approach; place ureteral stents to avoid ureteral injury (diverticula often adhere to the ureter). Complications: ureteral injury/bleeding/adjacent-organ injury, UTI, prolonged extravasation, and late urinary fistula.
- Catheterization (CIC or indwelling) — for poor emptying with persistent symptoms after relieving obstruction, or in patients unfit/unwilling for surgery.
Self-Test
1. Where are most congenital bladder diverticula located? Near the ureterovesical junction.
2. Workup of an adult with a bladder diverticulum? History/physical (DRE in men); urinalysis, cytology, PSA if appropriate; upper-tract US (rule out hydronephrosis) and lower-tract CT ± VCUG; cystoscopy; urodynamics to exclude neurogenic dysfunction.
3. Causes of bladder diverticula in women? Dysfunctional voiding, urethral stricture, vaginal prolapse, bladder-neck hypertrophy, iatrogenic obstruction from anti-incontinence surgery.
4. Congenital vs acquired diverticula? Congenital: no cancer risk, smooth-walled bladder, may lack obstruction. Acquired: cancer risk, trabeculated thick-walled bladder, almost always obstructed.
5. Indications for intervention? Refractory symptoms, recurrent UTI, stones, suspected malignancy, upper-tract deterioration from obstruction/reflux.
6. Complications of diverticulectomy? Ureteral injury, bleeding, adjacent-organ injury, UTI, prolonged urinary extravasation, late urinary fistula.