Differentiation Between Bladder Diverticulum and Ureterocele
A bladder diverticulum is a herniation of bladder mucosa through the detrusor muscle fibers, while an ureterocele is a cystic dilation of the distal submucosal ureter that protrudes into the bladder lumen. 1, 2
Anatomical Differences
Bladder Diverticulum
- Outpouching of bladder mucosa through a weakness in the detrusor muscle
- Can occur anywhere in the bladder wall
- May be congenital or acquired (secondary to obstruction)
- Rare in women, more commonly associated with neurogenic or postoperative bladder 1
- May develop as a complication near a ureteral orifice
Ureterocele
- Cystic dilation of the terminal submucosal portion of the ureter
- Located specifically at the ureteral orifice
- Often associated with duplex collecting systems (in approximately 60% of cases) 2
- Can be orthotopic (entirely within the bladder) or ectopic (extending into the urethra)
Clinical Presentation
Bladder Diverticulum
- Recurrent urinary tract infections (UTIs) due to urinary stasis
- May cause obstruction if located near the bladder neck
- Can be asymptomatic if small
- When located near a ureteral orifice, may be associated with vesicoureteral reflux 1
Ureterocele
- Recurrent UTIs (present in approximately 63% of cases) 2
- Urinary obstruction
- Hydronephrosis of the affected kidney
- May cause bladder outlet obstruction if large or ectopic
- Can be associated with duplex collecting systems and vesicoureteral reflux 2
Diagnostic Imaging
Bladder Diverticulum
- Best visualized on:
- Appears as an outpouching from the bladder wall with a visible neck
Ureterocele
- Best visualized on:
- Ultrasonography (appears as a cystic structure within the bladder) 2
- VCUG (filling defect in the bladder)
- CTU or MR urography
- Cystoscopy (appears as a balloon-like structure at ureteral orifice)
Complications
Bladder Diverticulum
- Urinary stasis leading to recurrent UTIs
- Stone formation within the diverticulum
- Potential for malignant transformation
- When located near ureteral orifice, may cause vesicoureteral reflux 1
Ureterocele
- Obstruction of the affected ureter leading to hydronephrosis
- Renal scarring (detected in approximately 32% of cases) 2
- Bladder outlet obstruction
- May be associated with duplex collecting systems
- Can lead to renal dysfunction if obstruction is prolonged
Management Approaches
Bladder Diverticulum
- Surgical excision (diverticulectomy) for symptomatic cases
- May require transvesical or extravesical approach depending on location 3
- Treatment of underlying obstruction if present
Ureterocele
- Endoscopic incision (appropriate for some cases)
- Upper pole nephrectomy if associated with non-functioning upper pole of duplex system 2
- Bladder level reconstruction
- Ureteral reimplantation
Important Clinical Considerations
- When a bladder diverticulum is located near a ureteral orifice, VCUG should be performed to evaluate for vesicoureteral reflux 1
- In rare cases, a ureterocele can be associated with the development of a secondary bladder diverticulum, complicating diagnosis and treatment 4, 5
- MRI provides excellent soft tissue contrast and is optimal for complex urinary tract anomalies 1
- In pediatric patients with recurrent UTIs, both conditions should be considered in the differential diagnosis 2, 3
Pitfalls in Diagnosis
- Ureteroceles may be missed on standard ultrasonography if collapsed
- Bladder diverticula can be confused with other pelvic cystic structures
- Complex cases with both conditions present simultaneously may lead to diagnostic challenges 4, 5
- Proper imaging with multiple modalities may be necessary for definitive diagnosis in complex cases