Illustration of a ureteral polyp causing obstruction

Rare Cause of UPJ Obstruction: What to Know About Ureteral Polyps

Samir D’Costa in Health & Wellness December 2025 • 3 min read.

"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.

Ureteral Polyps: An Uncommon Culprit

Illustration of a ureteral polyp causing obstruction

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.

Despite being the most common benign tumors of the ureter, ureteral polyps are still a rare cause of UPJ obstruction, accounting for only about 0.5% of cases in children undergoing pyeloplasty, a surgical procedure to correct UPJ obstruction. They tend to affect boys more often than girls and are more frequently found on the left side.

Abdominal or flank pain, which may come and go.
Hematuria (blood in the urine).
Nausea and vomiting.
Nonspecific gastrointestinal symptoms.

Diagnosis can be challenging as their symptoms overlap with more common conditions. In the case described, the patient presented with flank pain, nausea, and vomiting, leading to initial suspicion of a urinary stone. However, imaging studies revealed a narrowing at the UPJ that was eventually identified as a polyp during surgery.

Key Takeaways

Ureteral polyps are a rare but important cause of UPJ obstruction, especially in children presenting with atypical symptoms.

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.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.3941/jrcr.v6i7.1076, Alternate LINK

Title: Ureteral Fibroepithelial Polyp Causing Urinary Obstruction

Subject: Radiology, Nuclear Medicine and imaging

Journal: Journal of Radiology Case Reports

Publisher: EduRad

Authors: John D Mackenzie, Melissa L Shive, Laurence Baskin, Catherine Harris, Michael Bonham

Published: 2012-07-20

Everything You Need To Know

What are ureteral polyps?

Ureteral polyps are benign growths arising from mesodermal tissue, typically found within the ureter. These growths are composed of a fibrovascular core, covered by normal urothelium, which is the lining of the urinary tract. Although they can occur anywhere along the ureter, they are most frequently located in the upper third, near the Ureteropelvic Junction (UPJ).

Why are ureteral polyps important?

Ureteral polyps are significant because they can lead to Ureteropelvic Junction (UPJ) obstruction, a blockage that can cause urine buildup and potential kidney damage. This is particularly important in children where typical causes of UPJ obstruction, such as stones or congenital abnormalities, might be considered first. Recognizing ureteral polyps as a possible cause ensures appropriate diagnosis and timely intervention, thus preventing further complications.

What are the symptoms of ureteral polyps?

Common symptoms of ureteral polyps include abdominal or flank pain, which may come and go, Hematuria (blood in the urine), nausea and vomiting, and nonspecific gastrointestinal symptoms. These symptoms can easily be mistaken for other more common conditions like urinary stones. Due to overlapping symptoms, a comprehensive diagnostic approach, including imaging studies, is often necessary to identify the presence of a ureteral polyp as the underlying cause of the obstruction.

How are ureteral polyps treated?

Treatment for ureteral polyps typically involves surgical removal. The surgical approach will depend on the specific location and size of the polyp, as well as the overall condition of the patient. In the specific case outlined, the obstruction caused by the ureteral polyp was resolved through surgery, which highlights the importance of considering this rare etiology when typical findings are absent.

What is Ureteropelvic Junction (UPJ) obstruction and how do ureteral polyps relate to it?

The term "Ureteropelvic Junction (UPJ) obstruction" refers to a blockage at the point where the ureter connects to the kidney. Ureteral polyps are a less common cause of this obstruction. If left untreated, UPJ obstruction can result in the buildup of urine in the kidney, potentially leading to kidney damage. While other causes like stones or congenital abnormalities are often suspected, ureteral polyps underscore the need for thorough diagnostic evaluations in cases with atypical symptoms, especially in children.