Authors: Chengpin Tao, Yongsheng Cao, Tao Zhang
Categories: Letter to the Editor
Source: Quantitative Imaging in Medicine and Surgery
Doi: 10.21037/qims-24-648
Congenital bladder diverticulum is relatively uncommon among children, with an estimated prevalence of 1.7% (1). Bladder diverticulum in the pediatric population is predominantly observed in males, a distinctive clinical feature that might be attributed to the transient intrauterine bladder outlet obstruction theory in male fetuses. This hypothesis has been put forth by certain researchers to elucidate bladder dysfunction occurring in male infants with severe vesicoureteral reflux (VUR), positing that this phenomenon might arise from embryonic development factors such as urethral angulation, Cowper gland cysts, or posterior urethral valves (2).
A bladder diverticulum is a pouch-like protrusion of the bladder mucosa through the muscular layer of the bladder wall. They can be categorized into congenital (primary) and acquired (secondary) types (3). Congenital bladder diverticulum is more common in children and may occur due to the weakness of the muscular layer at the vesicoureteral junction or the posterior urethral valve, leading to localized eversion (4). The wall of this type of diverticulum contains muscle fibers from the bladder wall. On the other hand, acquired bladder diverticulum often develops as a result of lower urinary tract obstruction, such as urethral stricture, bladder outlet obstruction, and prostate enlargement. In this scenario, increased intravesical pressure and compression of the bladder wall cause the bladder mucosa to protrude outward through the gaps in the involuntary muscle, forming diverticula with mucosal trabeculae but without muscle fibers. These diverticula are typically small, numerous, and accompanied by severe bladder trabeculation.
In the early stages of congenital bladder diverticulum, clinical symptoms may not be apparent. As the condition progresses, complications like infection, stones, rupture, and even malignancy can arise. Clinical presentations can include hematuria, urinary frequency, urgency, incontinence, difficulty urinating, and abdominal or lower back pain (5). Larger diverticula can lead to prolapse, causing posterior urethral obstruction, bladder perforation, and urinoma formation. Currently, there is a lack of standardized imaging criteria guiding the diagnosis and management of congenital bladder diverticulum in pediatric patients. Further exploration is warranted to establish optimal imaging modalities for accurate diagnosis and assessment of treatment outcomes. Herein, we present compiled imaging data on the diagnostic approaches and findings of congenital bladder diverticulum in 10 pediatric cases admitted to our hospital from January 2015 to January 2023.
Between January 2015 and January 2023, ten cases of congenital bladder diverticulum were identified in pediatric patients. All procedures performed in this study were in accordance with the ethical standards of the Ethics Committee of Anhui Provincial Children’s Hospital (No. EYLL-2023-013) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patients’ parents or legal guardians for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.
All patients were male, ranging in age from 1.5 to 7 years, with an average age of 3.3 years. Clinical symptoms included febrile urinary tract infection (UTI), urinary incontinence, hematuria, urinary retention. The detailed patient information is shown in Table 1. After admission, all cases underwent urinary system ultrasonography (Figure 1), computed tomography (CT) (Figures 2-4) or magnetic resonance urography (MRU) (Figure 5), and voiding cystourethrography (VCUG) (Figure 6) examinations. Among these cases, 5 were found to have concomitant VUR (Figure 7). All patients were diagnosed with primary bladder diverticulum. Other system abnormalities were excluded through abdominal ultrasound and related examinations. Considering cost issues, we did not conduct additional genetic testing for congenital syndrome screening. Surgical interventions were performed for the management of congenital bladder diverticulum in pediatric patients. These interventions included laparoscopic bladder diverticulectomy and transvesical diverticulectomy. Additionally, cases complicated with VUR underwent ureteral reimplantation.
Figure 1 The abdominal ultrasound examination shows a cystic mass (black arrow) behind the bladder (blue arrow), with a visible channel connecting (white arrow) to the bladder. The size of the cystic mass can vary during the examination. The white box indicates the area where the blood flow signal is to be collected. In ultrasound imaging, red indicates blood flow towards the probe, and blue indicates flow away from it. “D” likely refers to the imaging depth.
Figure 2 The CT scan reveals a cystic shadow (black arrow) located behind the bladder (blue arrow), which communicates with the bladder. The bladder wall thickness is significantly increased, measuring approximately 8–10 mm. CT, computed tomography.
Figure 3 In the delayed phase of the enhanced CT scan, contrast agent uptake is visible in both the bladder (blue arrow) and the cystic mass (black arrow). CT, computed tomography.
Figure 4 In both the coronal and sagittal views of the CT scan, a cystic mass (black arrow) is observed behind the bladder (blue arrow), with contrast agent entering the mass. CT, computed tomography.
Figure 5 The MRI examination reveals a cystic signal (red arrow) located behind the bladder (blue arrow), exhibiting long T1 and long T2 signals. MRI, magnetic resonance imaging.
Figure 6 The VCUG examination shows contrast entering the bladder (blue arrow) followed by a posterior cystic protrusion (black arrow), with contrast material entering it and communicating with the bladder. R, right; VCUG, voiding cystourethrography.
Figure 7 The VCUG examination reveals a cystic protrusion (black arrow) located behind the bladder (blue arrow), with contrast material entering it and communicating with the bladder. Additionally, contrast reflux is observed into the R ureters and right renal pelvis (red arrow). VCUG, voiding cystourethrography; R, right.
In our study, we evaluated the performance of ultrasound, CT, magnetic resonance imaging (MRI), and VCUG in diagnosing bladder diverticula in 10 pediatric cases. The results showed that the sensitivity of ultrasound was 60%, while both CT and MRI had a sensitivity of 70%. In contrast, VCUG demonstrated a sensitivity of 100%. This indicates that VCUG accurately diagnosed all cases of bladder diverticulum, outperforming ultrasound, CT, and MRI in this regard. All 10 pediatric cases underwent successful surgery, with operative durations ranging from 83 to 290 minutes and an average of 207 minutes. Postoperative histopathological examination revealed the presence of residual stratified squamous epithelium, with fibrous tissue above and below the epithelium showing a sparse distribution of smooth muscle bundles consistent with the diagnosis of primary bladder diverticulum (Figure 8).
Figure 8 Postoperative pathology suggests the presence of a sparsely distributed smooth muscle tract (hematoxylin and eosin stain, magnification ×100).
Follow-up conducted over a period of 10 months to 2 years postoperatively demonstrated the disappearance of symptoms such as urinary incontinence and urinary retention in the patients. There were no further occurrences of UTIs. Postoperative follow-up abdominal color Doppler ultrasound examinations indicated the disappearance of the bladder diverticulum (Figure 9). VCUG examination revealed no bladder diverticulum and no recurrence of VUR (Figure 10).
Figure 9 Postoperative follow-up abdominal color Doppler ultrasound (blue arrow) showed the disappearance of the diverticulum around the bladder.
Figure 10 Postoperative follow-up VCUG examination revealed no bladder diverticulum or vesicoureteral reflux. R, right; VCUG, voiding cystourethrography.
The etiology of congenital bladder diverticulum in children remains unclear. According to Linke* et al. (6) it may result from incomplete fusion of muscular tissues during embryonic development. Garat et al. (7) found scant detrusor muscle fibers in histological examinations, suggesting a congenital muscle defect contributing to diverticulum formation. Psutka et al. *(8) also implicated detrusor muscle dysfunction. The pathogenesis and etiology of congenital bladder diverticulum continue to necessitate further investigation. Acquired bladder diverticulum is more frequently encountered in adults, whereas its occurrence in childhood could be secondary to neurogenic conditions in children, such as spina bifida, spinal cord injury, and meningocele (9). It is also seen in disease entities such as prune belly syndrome, Ehlers-Danlos syndrome, cutis laxa syndrome, occipital horn syndrome (OHS), Menkes disease, and Williams-Beuren syndrome (10). Alternatively, previous bladder surgeries or other medical factors might contribute to bladder outlet obstruction, consequently resulting in the development of small, multiple diverticula accompanied by marked bladder trabeculation (11).
Congenital bladder diverticulum might be detected prenatally through ultrasound, although it is more frequently identified during screenings for UTIs, obstruction, hematuria, or incontinence. Medical history and physical examinations often lack specificity. Laboratory tests may suggest UTIs or hematuria. Ultrasound examinations during different bladder filling stages can reveal the presence of the diverticulum. On ultrasound images, the diverticulum typically appears as a round or hypoechoic structure, originating near the bladder base or ureteral orifice. VCUG during the voiding phase serves as the gold standard for diagnosing bladder diverticulum (12). Additionally, VCUG can reveal VUR and provide information about the posterior urethral anatomy. During bladder filling, the diverticulum appears smaller due to bladder filling; during voiding, the bladder contracts and the diverticulum enlarges (13). Complementary diagnostic methods for bladder diverticulum include CT scans, MRI, and intravenous pyelography (IVP). CT and MRI scans can display the morphology and size of the bladder diverticulum, as well as its relative position to surrounding tissues. In patients with upper urinary tract involvement, dimercaptosuccinic acid (DMSA) renal scans can elucidate different kidney functions and the presence of renal scars.
Smaller bladder diverticula typically present with no significant clinical symptoms, while larger diverticula can lead to difficulties in urination, hematuria, UTIs, and urinary retention (14). Based on their relationship with the ureteral orifice, bladder diverticula can be classified into two paraureteral diverticula, where the ureteral orifice is within the diverticulum, and perivesical diverticula, where the ureteral orifice is near the diverticulum. Diverticula unrelated to the ureteral orifice are referred to as posterior lateral diverticula (15). Approximately 90% of primary congenital diverticula are located near the ureteral orifice, while the remaining 10% occur in the posterior lateral position (9). Posterior lateral diverticula often have a larger volume and symptomatic presentation. Children with posterior lateral diverticula typically exhibit urinary stasis, retention, recurrent infections, and stone formation (2). In this study, there were 2 cases of posterior lateral diverticula, 3 cases of paraureteral diverticula, and 4 cases of perivesical diverticula. Diverticula originate from the weak area between the trigone, derived from the mesoderm, and the bladder dome, derived from the endoderm. They form as outpouchings of the mucosa, usually unrelated to VUR or other renal abnormalities. Additionally, it is worth noting the distinct differences between congenital urethral diverticula and Hutch diverticula. Congenital urethral diverticula are sac-like dilations of the urethral mucosa or submucosa, often associated with glands near the urethral meatus. In contrast, Hutch diverticula refer to sac-like dilations around the periurethral glands near the bladder neck, typically associated with the posterior wall near the bladder neck and possibly related to VUR (16). Hence, although both are sac-like dilations of the urethra, they may differ in location, etiology, and clinical presentation.
In clinical practice, incidentally discovered asymptomatic diverticula typically do not require special treatment and can be managed through regular follow-up observations (17). This can be achieved by performing annual color Doppler ultrasound examinations and analyzing urinalysis. Surgical intervention becomes necessary when complications arise, such as difficulties in urination, stone formation, hematuria, UTIs, or urinary retention (18). Surgical approaches for bladder diverticula include intravesical and extravesical methods (19). With the advancements in minimally invasive urological instruments, traditional laparoscopy, and robotic-assisted techniques, there has been an increasing number of reports on minimally invasive treatments for bladder diverticula (20,21). The vast majority of primary bladder diverticula are closely related to the ureteral orifice. Through an intravesical approach, the anatomical structure of the ureter and the diverticulum can be evaluated. This method also allows for the correction of any accompanying pathology (such as refluxing ureteral reimplantation). When considering surgery through an intravesical approach, various factors need to be taken into account, especially in the case of diverticulum excision. Factors include the size, location, and number of diverticula, their proximity to the ureteral orifice, and the potential need for concurrent procedures (20). For symptomatic diverticula, diverticulectomy can ease urination difficulties and recurrent UTIs, preventing kidney function decline and scar formation (22). Early detection and treatment prevent symptom progression and complications, improving prognosis and quality of life. Prompt management minimizes bladder and tissue damage, preserving bladder function.
Congenital bladder diverticulum in children, though rare, can have serious consequences if left untreated, affecting their health and well-being. Ultrasound serves as a preliminary diagnostic tool for bladder diverticulum. CT and MRI serve as diagnostic tools for bladder diverticulum, with VCUG considered the gold standard for diagnosis. Additionally, VCUG can identify concurrent bladder VUR. These findings underscore the importance of timely surgical intervention and radiological monitoring in managing congenital bladder diverticulum in pediatric patients, ensuring favorable long-term outcomes and patient well-being.
The authors would like to thank the medical and nursing staff of the Urology Department at Anhui Provincial Children’s Hospital for their support and assistance with data collection. The authors also extend their gratitude to John Smith for his thorough review and valuable language editing assistance on the manuscript.
Funding: None.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the Ethics Committee of Anhui Provincial Children’s Hospital (No. EYLL-2023-013) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patients’ parents or legal guardians for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.