A ureterocele is a congenital condition in which there is swelling or dilation of the distal portion of the ureter (the tube that carries urine from the kidney to the bladder) at the point it enters the bladder. This swivel of the ureter creates balloon-like sac while in the bladder wall, which may result in partial or complete obstruction of the normal flow of urine.

Ureteroceles are usually classified in general terms of where they are situated and with what associated anatomical abnormalities (e.g. clot liberation). There are two main types of ureteroceles:

• Intravesical ureterocele (orthotopic): is located completely within the bladder.
• Ectopic ureterocele: extends outside of the bladder into the bladder neck or urethra. Ectopic ureteroceles are more often seen in children, especially girls under the age of two, and associated with duplicated collecting systems (when a kidney have two ureters instead of one).

Ureteroceles are congenital anomalies and while they may be detectable right after birth, the attendant symptoms may not be manifest until later in childhood, especially in milder instances. Some individuals are incidentally diagnosed with ureteroceles on imaging studies for other urinary complaints.

An ureterocele can obstruct the urine flow which can cause the urine to back up into the kidney (known as vesicoureteral reflux). This can cause urinary obstruction, urinary retention, urinary tract infections (UTIs), and eventually possible kidney damage over time due to the backpressure in the urinary tract.

Due to more routine prenatal imaging, with ultrasounds, there has been an increase in the identification of ureteroceles antepartum, meaning before birth; thus allowing for better risk stratification and management going forward to avoid long-term problems.

Ureterocele is a congenital condition that occurs before birth (in utero), and is related to improper development of the ureter. Ureterocele can occur in the right ureter or the left ureter but happens equally in both ureters, and it cannot be prevented.

Developmental Cause:

During fetal life the ureter section (the ureteric bud) develops from the ureteric bud that connects to the bladder. If the junction of the ureteric opening formed in the muscle wall of the bladder is too narrow (stenotic ureteric orifice), backflow of urine will occur and the end of the ureter will balloon, forming an ureterocele.

Associated Factors:

• Duplicated collecting systems – occur in approximately 80% of cases, where one kidney (usually the ipsilateral kidney) has a second ureter draining a part of the kidney’s collecting system. The upper pole ureter usually ends in an ureterocele.
• Ectopic ureter or ectopic insertion – the ureter drains into an abnormal drainage site such as the bladder neck or urethra, causing obstruction of the drainage site.
• Obstruction at the ureterovesical junction (UV junction of the ureter at the bladder nephron) – stenosis at the junction of the ureter and bladder leads to obstructed drainage of urine from the ureter to the bladder causing ballooning of the ureter.
• Genetic/hint of traits – congenital urinary anomalies appear to clump in family but there is no strong evidence of hereditary UMN. No link to any specific genes.

Other Notes

At this time, after thorough search, there are no environmental or maternal risk factors associated with ureterocele outcomes, nor is there any thought to be risk specific to parenting or bilateral risk. Most cases are spontaneously arising during fetal life. Ureterocele is most often diagnosed in pregnancy on sonography, or after urinary tract symptomatic issues have developed.

Ureterocele is a congenital defect, meaning that it exists at birth. It is not reversible and will not go away for any reason. Ureterocele is not caused by poor lifestyle, infections, injuries, or anything done “wrong” during pregnancy. It is thought that ureterocele happens randomly during fetal development.

In Infants and Children:

Ureteroceles are mostly diagnosed through prenatal ultrasound and indicated by findings of hydronephrosis (swelling of the kidney from backflow of urine). After birth, children can present with UTIs, abdominal masses, or urinary hesitancy eventually leading to diagnosis of ureterocele.

In Adults:

Occasionally, ureteroceles will be asymptomatic and maybe discovered incidentally while a patient is being evaluated for other urinary issues such as reflux. Common symptoms when ureteroceles do cause symptoms in adults are recurrent UTIs, bladder outlet obstruction, or urinary retention.

The signs and symptoms of ureterocele depend on the size, location, symptom type (obstruction/infection) and if associated with any other anatomical abnormalities, such as duplicated ureters. A portion of those with ureterocele may be asymptomatic while others may have some variety of urinary abnormality.

In Infants and Children

• Fever, likely the consequence of urinary tract infection (UTI)
• Foul-smelling or cloudy urine
• Poor feeds or irritability (infants)
• Failure to thrive
• Abdominal or flank mass/pain
• Hydronephrosis (identified on prenatal or postnatal ultrasound)
• Voiding dysfunction or having difficulty voiding
• Enuresis (involuntary voiding whether in the day or night)

In Adults

• Frequent urination
• Dysuria (painful urination)
• Urgent need to urinate or urgency/incontinence
• Recurring urinary tract infections
• Hematuria (blood in the urine)
• Flank or back pain, especially when hydronephrosis is present
• Bladder or ureteric stones potentially the result of stagnant urine
• Prolapse of the ureterocele tissue through the urethra into the vagina (in females)

Complications If Left Untreated

• Progressive kidney damage from chronic obstruction
• Sepsis, in severe untreated infections
• Bladder outlet obstruction
• Renal scarring and permanent loss of kidney function in advanced cases.

The process of diagnosing an ureterocele typically involves imaging and laboratory tests. Diagnoses are often pursued due to recurrent urinary tract infections (UTIs), hydronephrosis, or unexplained urinary symptoms.

Prenatal Ultrasound:

Ureteroceles are frequently detected during routine prenatal ultrasound, particularly in the 28th week of gestation, when the fetal urinary tract is optimally visualized. The presence of hydronephrosis (i.e., swelling of one or both kidneys) may raise the suspicion of a ureterocele and warrant further postnatal assessment.

Postnatal Imaging:

1. Ultrasound (Renal and Bladder):
   • First imaging study done for evaluation.
   • Can detect a fluid-filled sac at the bladder end of the ureter.
   • Identifies hydronephrosis and other anatomic abnormalities.
2. Voiding Cystourethrogram (VCUG):
   • The procedure involves instilling contrast dye into the bladder and taking X-rays with the patient voiding.
   • Evaluates for vesicoureteral reflux (VUR), which is commonly associated with ureteroceles.
3. Magnetic Resonance Urography (MRU) or CT Urogram:
   • Provides clear visualization for anatomy of the urinary tract.
   • MRU is the study of choice in children to avoid radiation, especially in complex or suspected duplicating ureters.
4. Intravenous Pyelogram (IVP):
   • This is an older imaging modality, but it is sometimes used.
   • IVPs, also called intravenous urography (IVU), uses a contrast dye that is injected into the patient to picture the kidneys, ureters, and bladder.
   • IVPs can help detect ureteroceles, any obstruction, or impaired flow.
5. Cystoscopy:
   • This involves direct visual inspection/assessment of the bladder with a thin, flexible camera (cystoscope).
   • Cystoscopy confirms the presence of the ureterocele and its size and position.
   • It can be useful in surgical planning and/or treatment.
6. Urinalysis and Urine Culture:
   • Can check for infection, hematuria (blood), pyuria (pus cells).
7. Renal Scan (DMSA or MAG3):
   • Provides information about kidney function and how the urine drains.
   • DMSA assesses scarring or differential renal function. MAG3 can assess obstructive and non- obstructive patterns.
8. Blood Work:
   • Complete blood count (CBC) which could give evidence of infection.
   • Tests for kidney function (creatinine, BUN).
   • C-reactive protein (CRP) to assess systemic inflammation.

Management of ureterocele depends on a number of factors, including:

• Type (intravesical vs ectopic)
  • A duplicated collecting system
  • Obstruction, reflux
  • Age of the child, symptoms
  • Goals of management
  • Relieve urinary obstruction
  • Avoid or manage infection
  • Conserve renal function
  • Resolve vesicoureteral reflux
  • Decompress or excise ureterocele

Non-Surgical Management

In asymptomatic patients or patients with mild symptoms and no obstruction, follow-up for observation may be appropriate, especially if the patient is an adult. Prophylactic antibiotics may also be used to treat or prevent UTIs, and can even be used prenatally, if there is significant dilation on the prenatal ultrasound.

Surgical Treatment Options:

1. Endoscopic Puncture/Incision:
   • Most common method with minimal invasive approach
   • Small incision is made in the ureterocele and allows for urine to flow freely into the bladder.This can be performed, in adults and children, endoscopically with a cystoscopeTypically the first line of therapy.
   • If obstruction or reflux persist, follow up surgery may be required.
2. Ureteral Reimplantation:
   • Ureter is reattached to a different site in the bladder to promote urinary flow.
   • Commonly used in ectopic ureteroceles or where severe reflux is present.
   • May be completed in an open or laparoscopic fashion.
3. Upper Pole Heminephrectomy:
   • In duplicated systems with a nonfunctional upper pole of kidney, that portion may be partially resected.
   • This method would be chosen in cases where the damaged area cannot be salvaged.
4. Ureteropyelostomy or Ureteroureterostomy:
   • The affected ureter is anastomosed either to a normally positioned ureter or directly to the renal pelvis.
   • This is commonly used in the setting of duplicated ureters.
5. Bladder Reconstruction:
   • Bladder reconstruction is rarely needed.
   • Usually used in the setting of extensive distortion of bladder anatomy or poor function.
6. Watchful Waiting: In selected adults with no symptoms or kidney damage, careful monitoring over time may be sufficient. This conservative approach avoids unnecessary intervention unless the condition worsens.

Ureterocele is an uncommon but significant condition of the urinary tract that is often present at birth. Untreated, ureterocele can block urine outflow, become infected, and over time warrant wasting kidney function. While most ureteroceles are identified in infancy or early childhood due to prenatal or early life imaging, some may persist undiagnosed until adulthood.

Fortunately, most patients with ureterocele will live healthy, normal lives with documented treatment or close follow up after diagnosis. Many medical treatments are minimally invasive, and there are multiple elegant solutions to fixing ureteroceles today that prevent significant loss of kidney function.

Recognizing ureterocele is essential for parents, patients, and providers to identify early and prevent lag time in treatment. The implications of ureterocele are very manageable and, with appropriate care, the potential for severe complications can be avoided with proper care.

• Tanagho, E. A., & McAninch, J. W. (2019). Smith & Tenaha’s general urology (19th Ed.). McGraw-Hill Education.
• Kumar, S., & Gearhart, J. P. (2023). Ureterocele. In R. A. Wein, A. J. Kavoussi, A. C. Novick, L. R. Partin, & C. A. Peters (Eds.), Campbell-Walsh-Wein Urology (12th ed.). Elsevier.
• Medscape. (2024). Ureterocele Imaging.
• Nguyen, H. T., Herndon, C. D., Cooper, C., Gatti, J., Kirsch, A., Kokorowski, P& Yerkes, E. (2010). The Society for Fetal Urology consensus statement on the evaluation and management of antenatal hydronephrosis. Journal of Pediatric
• UpToDate. (2024). Ureterocele: Clinical manifestations, diagnosis, and management. Retrieved June 20, 2025 Urology, 6(3), 212–231.