Can a ureterocele occur in a kidney with a single, non-duplicated (non-duplex) collecting system?

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Last updated: September 27, 2026 • View editorial policy

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Can Ureterocele Occur in a Non-Duplicated (Single) Collecting System?

Yes, ureteroceles absolutely can occur in kidneys with single, non-duplicated collecting systems, though they are less common than in duplex systems.

Epidemiology and Frequency

While ureteroceles are classically associated with duplicated collecting systems, single-system ureteroceles represent a well-documented entity. In one pediatric series, 9 children had ureteroceles with single collecting systems compared to 63 with duplex ureteroceles over an 8-year period—demonstrating that single-system ureteroceles comprise approximately 12-15% of all ureteroceles 1. Current guidelines recognize ureterocele as a cause of urinary tract dilation in both obstructive and non-obstructive contexts, without restricting the diagnosis to duplex systems 2.

Clinical Characteristics

Single-system ureteroceles differ from their duplex counterparts in several important ways:

  • Gender distribution: Earlier reports suggested male predominance in single-system ectopic ureteroceles, but more recent data show equal gender distribution 1
  • Associated anomalies: Single-system ureteroceles, particularly when associated with dysplastic kidneys, carry a significantly higher risk (63%) of other congenital anomalies including VACTERL association, congenital heart disease, and other genitourinary malformations 3
  • Adult presentation: In adults, single-system ureteroceles are actually the predominant form, representing 94% of cases in one series, with duplex ureteroceles being rare 4

Clinical Presentations to Recognize

Single-system ureteroceles present with:

  • Recurrent urinary tract infections (most common)
  • Urinary retention or obstructive symptoms
  • Hematuria
  • Pelvic mass
  • Urinary dribbling or incontinence (especially in females with ectopic insertion)
  • Epididymitis in males
  • Low back pain (adults)
  • Associated stones (64% in adult series) 4

Diagnostic Approach

Key imaging findings that should raise suspicion:

  1. Ultrasound: Cystic dilation at the ureterovesical junction, hydroureteronephrosis
  2. VCUG: Characteristic "cobra head" or filling defect in bladder
  3. Critical pitfall: Nonvisualization of one kidney on imaging in association with any of the above symptoms should strongly suggest a single ectopic ureter with possible ureterocele 5

Management Considerations

Single-system ureteroceles require individualized assessment but generally follow this approach:

  • High infection risk: Unlike some children with multicystic dysplastic kidney, this subgroup has increased infection risk and must be correctly identified for tailored management 3
  • Conservative management: Careful evaluation with long-term surveillance is appropriate for many cases 1
  • Spontaneous resolution: In cases with cystic/dysplastic kidneys, involution and reabsorption can occur with ureterocele collapse 1
  • Endoscopic intervention: First-line for symptomatic cases without severe proximal dilation 4
  • Watch for complications: De novo vesicoureteral reflux occurs in approximately 38.5% after endoscopic treatment 4

Common Pitfalls to Avoid

  1. Don't assume all ureteroceles are duplex: This outdated assumption delays diagnosis
  2. Screen for associated anomalies: Particularly in single-system cases with dysplastic kidneys
  3. Don't miss ectopic insertion: Pay particular attention to ureteral insertion site whenever reflux is present 5
  4. Consider prophylactic antibiotics: Children with known ureterocele are considered high-risk for UTI per current guidelines 2

The bottom line: Ureteroceles in single collecting systems are real, clinically significant, and require the same diagnostic vigilance as duplex-system ureteroceles, with particular attention to associated congenital anomalies.

References

4
Research

[Ureterocele in adults based on a series of 14 cases].

Progres en urologie : journal de l'Association francaise d'urologie et de la Societe francaise d'urologie, 2005

5
Research

The single ectopic ureter.

AJR. American journal of roentgenology, 1976

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.