Rare Cause of UPJ Obstruction: What to Know About Ureteral Polyps
"Understanding ureteral fibroepithelial polyps: A rare but important cause of urinary obstruction, especially in children."
Ureteropelvic junction (UPJ) obstruction, a blockage where the ureter connects to the kidney, can lead to a buildup of urine and potential kidney damage. While common culprits like stones and congenital abnormalities are often suspected, a less familiar cause lurks in the shadows: ureteral polyps.
Ureteral polyps are benign growths that, although rare, can cause significant problems, particularly in children. Understanding these polyps, how they're diagnosed, and what treatment options exist is crucial for prompt and effective care.
This article explores a unique case of a nine-year-old boy whose UPJ obstruction was ultimately attributed to a ureteral polyp, highlighting the diagnostic challenges and emphasizing the importance of considering this rare etiology when typical findings are absent.
From First Reports to Rare Pediatric Cases
Ureteropelvic junction obstruction is a blockage of urine flow from the renal pelvis into the ureter. Fibroepithelial polyps were first described in a clinical setting by Berger et al., according to one case report. Subsequent reports included a nine-year-old boy with stable grade 2 left hydronephrosis and a 57-year-old woman with UPJ obstruction caused by a ureteral polyp.
Ureteral Polyps: An Uncommon Culprit
Ureteral fibroepithelial polyps are benign growths of mesodermal origin, meaning they arise from the same type of tissue that forms connective tissues in the body. These polyps consist of a fibrovascular core covered by normal urothelium, the lining of the urinary tract. While they can occur anywhere along the ureter, they're most commonly found in the upper third, near the UPJ.
- Abdominal or flank pain, which may come and go.
- Hematuria (blood in the urine).
- Nausea and vomiting.
- Nonspecific gastrointestinal symptoms.
Imaging and Classification Advances
Recent reports describe MRI as a possible way to visualize intraluminal lesions without radiation and distinguish them from aberrant vessels causing UPJ obstruction. A 2025 narrative review identifies ultrasound, computed tomography, and intravenous pyelography as diagnostic imaging methods used in children with fibroepithelial polyps. Other reported CT findings include left hydronephrosis, proximal ureteral dilation to 8 mm, and calcification at the UPJ.
Rarity Limits the Evidence
The PubMed search material describes ureteral fibroepithelial polyps as relatively rare, benign tumors. Their rarity means that the available evidence is represented in a focused search result rather than a broad summary of common disease patterns. This limited visibility can make the condition easy to overlook when evaluating ureteral obstruction.
Key Takeaways
Ureteral polyps are a rare but important cause of UPJ obstruction, especially in children presenting with atypical symptoms.
Clinical Patterns in Children
A 2023 study retrospectively reviewed children who underwent primary Anderson-Hynes pyeloplasty for UPJ obstruction caused by polyps. The study examined clinical manifestations, preoperative differential renal function, ultrasound parameters, and dynamic renograms. Its stated objective was to explore factors associated with supranormal preoperative differential renal function.
Planning Reconstruction More Precisely
A 2024 case series argues that polyps should be considered a potential cause of ureteral obstruction during reconstruction. Its authors hypothesized that performing a retrograde pyelogram before reconstruction could help surgeons plan treatment for this rare anomaly. The condition is especially noted as a rare cause of UPJ obstruction in children, making recognition important for diagnosis and treatment planning.
Keeping Rare Causes in the Differential
UPJ obstruction is a blockage in the renal pelvis, the funnel-like part of the kidney that collects urine before it enters the ureter. A case report of a 57-year-old woman with polyp-related UPJ obstruction emphasizes considering ureteral polyps when forming a differential diagnosis. Together, these sources place rare polyp-related obstruction within the broader clinical problem of identifying causes of impaired urine drainage.
Diagnostic imaging, particularly retrograde pyelography and magnetic resonance urography, plays a crucial role in identifying these polyps.
A high index of clinical suspicion and careful evaluation of imaging studies are essential for accurate diagnosis and timely surgical intervention, typically involving pyeloplasty or ureteroscopic resection.