Bladder diverticulum is a fluid-filled outpouching extending outward from the bladder wall. The acquired form is most common, occurring due to mucosal herniation through areas of muscular weakness from detrusor muscle hypertrophy in the setting of bladder outlet obstruction (BPH, urethral stricture, neurogenic bladder). The congenital form is seen in children and is usually called Hutch diverticulum (near the ureterovesical junction). Acquired diverticula are typically narrow-necked outpouchings and lack muscle layer (pseudodiverticulum — only mucosa and serosa). On CT urography, they are recognized as fluid-filled structures extending outward from the bladder wall with narrow neck connection to the bladder lumen; opaque urine accumulation within the diverticulum in delayed phase confirms the diagnosis. Diverticula are usually multiple and located on the lateral walls or posterolateral region of the bladder. Clinical significance: (1) infection risk due to incomplete emptying and stasis; (2) stone formation within diverticulum; (3) risk of tumor development within diverticulum (2-7%) — since diverticulum wall lacks muscle layer, tumor undergoes early perivesical invasion and staging is difficult. Large diverticula may compress the ureteral orifice causing obstructive uropathy.
Age Range
40-85
Peak Age
65
Gender
Male predominant
Prevalence
Common
The formation mechanism of acquired bladder diverticula is based on chronic bladder outlet obstruction: obstruction → compensatory detrusor muscle hypertrophy → force imbalance between muscle bundles → weak points (especially around ureteral orifices and vascular entry points) → herniation of mucosa and submucosa through these weak points with increased intravesical pressure → diverticulum formation. The diverticulum wall lacks muscle layer (only mucosa, submucosa, and adventitia) — hence also called 'pseudodiverticulum' and cannot actively contract → urinary stasis is inevitable. Imaging correlation: appears as a fluid-filled structure extending outward from the bladder wall on CT; the narrow neck is the connection point where the diverticulum opens into the bladder lumen — neck width determines emptying capacity (narrow neck = poor emptying = more stasis). In the delayed phase, contrast accumulates within the diverticulum because it cannot actively empty → opaque urine retention. Congenital Hutch diverticulum differs: originates from embryological Wolffian duct remnants and is located at the ureterovesical junction — predisposes to vesicoureteral reflux. Tumor development within diverticulum is an important complication: stasis → chronic irritation → urothelial metaplasia/dysplasia → carcinoma. Since the diverticulum wall lacks muscle layer, tumor undergoes early transmural invasion → T2 staging is difficult (T2a vs T2b distinction cannot be made) → prognosis worsens.
A fluid-filled outpouching extending outward from the bladder wall, connected to the bladder lumen by a narrow neck, is the pathognomonic finding of bladder diverticulum. Opaque urine accumulation within the diverticulum in the delayed phase confirms the connection. The narrow neck predisposes to infection, stone, and tumor complications due to incomplete emptying and stasis.
Appears as a narrow-necked fluid-filled outpouching extending outward from the bladder wall in delayed phase of CT urography. Opaque urine accumulation is seen within the diverticulum — this finding proves open connection with the bladder lumen. Neck width varies from a few mm to several cm. Diverticulum size can range from a few mm to >10 cm (giant diverticulum). Diverticulum wall is thin (<2 mm) and smooth; thickened or irregular wall should raise concern for infection or tumor. Multiple diverticula are common and may be bilateral.
Report Sentence
A narrow-necked diverticulum measuring __ mm is seen on the __ wall of the bladder, demonstrating opaque urine accumulation in the delayed phase.
An enhancing nodular structure on the diverticulum wall or within it suggests tumor development within the diverticulum. Incidence of urothelial carcinoma within diverticulum is 2-7% and since the diverticulum wall lacks muscle layer, tumor undergoes early perivesical invasion. It may appear as an enhancing wall nodule, irregular wall thickening, or polypoid intraluminal lesion. A dependent hyperdense structure at the diverticulum base may be a stone — lack of enhancement and high density (>200 HU) distinguishes stone from tumor.
Report Sentence
An enhancing __ mm nodular lesion is seen on the diverticulum wall, requiring evaluation for intradiverticular neoplasia; cystoscopy and biopsy are recommended.
Appears as an anechoic/hypoechoic fluid-filled structure extending outward from the distended bladder wall on B-mode US. The diverticulum neck may be visible as a focal defect in the bladder wall. Content is usually anechoic (clear urine); debris or echogenic material suggests infection or hemorrhage. Stone within diverticulum appears as hyperechoic focus + acoustic shadow but rolling stone sign may be lost due to narrow neck. US sensitivity for diverticulum detection is lower than CT — especially small or posteriorly located diverticula may be missed. Transrectal US (TRUS) better visualizes posterior diverticula.
Report Sentence
An anechoic outpouching measuring __ mm extending outward from the __ bladder wall is seen, consistent with bladder diverticulum.
Appears as a hyperintense (fluid signal) outpouching extending from the bladder wall on T2-weighted MRI. Urine within the diverticulum shows bright signal like urine in the bladder lumen on T2. The diverticulum wall may be visible as a thin hypointense line on T2. On contrast-enhanced T1, normal diverticulum wall shows minimal enhancement; focal nodular enhancement suggests tumor. On DWI, clear urine within diverticulum shows no restriction; focal diffusion restriction raises tumor suspicion. MRI is superior to CT for evaluating tumor within diverticulum — tumor detection is more sensitive with soft tissue contrast and DWI.
Report Sentence
Bladder diverticulum shows hyperintense fluid signal on T2 MRI with no focal enhancement/diffusion restriction in the diverticulum wall; no findings suggestive of malignancy.
Hyperdense calculus is seen within the diverticulum — shows same density characteristics as bladder stone but is localized within the diverticulum boundaries. Intradiverticular stone is usually immobile — cannot pass into the bladder lumen due to narrow neck and does not show rolling stone sign with positional change. This feature is an important difference from free bladder stone. Intradiverticular stone results from incomplete emptying and urinary stasis and has a higher likelihood of being infection stone (struvite).
Report Sentence
A calculus measuring __ mm with __ HU density is seen within the diverticulum; immobile due to diverticulum neck and may require diverticulectomy.
Accompanying bladder outlet obstruction findings are seen with acquired diverticula: trabeculation (irregular inner wall contour) due to detrusor muscle bundle hypertrophy, generalized wall thickening, prostatic hypertrophy (prostatic indentation at bladder base in males), increased post-void residual. Diverticula usually form at weak areas between trabeculation bands — intermediate forms including 'cellules' (small, shallow diverticula) and 'saccules' (deeper, neckless protrusions) may also be seen. Bilateral ureterhydronephrosis may accompany in advanced obstruction.
Report Sentence
Bladder wall trabeculation and multiple diverticula are seen, consistent with chronic bladder outlet obstruction.
Criteria
In adults; background of bladder outlet obstruction; multiple; lateral/posterolateral location; accompanying trabeculation; no muscle layer (pseudodiverticulum).
Distinct Features
Associated with BPH, urethral stricture, or neurogenic bladder. Trabeculation + multiple diverticula is pathognomonic. Treatment of underlying obstruction is mandatory.
Criteria
In children; usually solitary; near ureterovesical junction; may contain muscle layer (true diverticulum); VUR associated; no bladder outlet obstruction findings.
Distinct Features
Originates from embryological Wolffian duct remnants. Predisposes to vesicoureteral reflux. Usually requires surgical repair.
Criteria
Size >5-10 cm; may exceed bladder volume; significant stasis and complication risk; may compress ureter/bowel; appears as large fluid-filled structure on CT.
Distinct Features
Rare form requiring surgical treatment (diverticulectomy). Increased tumor development risk. Cystoscopic evaluation is mandatory.
Distinguishing Feature
Ureterocele is a cystic structure WITHIN the bladder lumen (intravesical); diverticulum extends OUTWARD from the bladder wall (extravesical). Ureterocele is located at the ureteral orifice and shows cobra-head sign.
Distinguishing Feature
Urothelial carcinoma is a solid enhancing mass; diverticulum is a fluid-filled structure. However, tumor may develop within diverticulum — irregular wall thickening and enhancing nodule should raise tumor suspicion.
Distinguishing Feature
Free bladder stone moves gravity-dependently (rolling stone); intradiverticular stone is immobile due to narrow neck and localized within diverticulum boundaries.
Distinguishing Feature
Urachal cyst is a midline structure extending from bladder dome toward umbilicus; diverticulum is on lateral/posterolateral wall with narrow neck connection to bladder lumen. Urachal cyst usually does not communicate with bladder lumen.
Urgency
routineManagement
surveillanceBiopsy
Not NeededFollow-up
12-monthAsymptomatic small diverticula do not require treatment but annual US follow-up is recommended. Symptomatic diverticula (recurrent UTI, stone formation, urinary retention) or large diverticula (>5 cm) may require diverticulectomy. Treatment of underlying obstruction (TURP for BPH, urethral stricture dilatation) is mandatory — otherwise new diverticula may form. In suspected intradiverticular tumor (irregular wall, enhancing nodule), cystoscopy + biopsy is mandatory — T staging is difficult since diverticulum wall lacks muscle layer and early surgery (partial or radical cystectomy) should be considered. In congenital Hutch diverticulum, VUR evaluation (VCUG) and surgical repair if needed are planned.
Bladder diverticulum is a common condition that usually develops secondary to bladder outlet obstruction (BPH). Complications include infection, stone formation, and TCC development (2-10%). Small asymptomatic diverticula are monitored. Symptomatic or large diverticula require surgery (diverticulectomy) and simultaneous relief of obstruction. Contrast-enhanced imaging is recommended in follow-up due to the risk of tumor development within.