Ureterocele

Overview

A ureterocele is a congenital condition where the end of the ureter, the tube that carries urine from the kidney to the bladder, balloons outward into the bladder. This cyst-like swelling occurs at the point where the ureter enters the bladder, potentially obstructing urine flow and leading to complications if left untreated.

Ureteroceles occur in approximately 1 in 4,000 births and are four to seven times more common in girls than boys. About 80% occur in association with a duplex kidney system, where the kidney has two ureters instead of one. There are two main types: intravesical (orthotopic) ureteroceles remain entirely within the bladder and are more common in adults with single ureter systems, while ectopic ureteroceles extend beyond the bladder into the urethra or bladder neck and are more common in children with duplex systems.

Many ureteroceles are now detected prenatally during routine ultrasound, appearing as hydronephrosis or a visible cystic structure at the bladder base. This early detection allows for monitoring and intervention before complications develop.

Symptoms

Symptoms vary depending on age at presentation and the type and size of the ureterocele.

In infants and young children, recurrent urinary tract infections are the most common presenting symptom. Parents may notice fever without an obvious source, unusual fussiness, poor feeding, or failure to thrive. A palpable abdominal mass may be present in some infants. When detected prenatally, the baby may be asymptomatic at birth and only identified through postnatal imaging follow-up.

Older children may experience abdominal or flank pain, difficulty urinating with straining, a weak urine stream, urinary frequency and urgency, daytime wetting, bedwetting, or blood in urine.

Adults are often diagnosed incidentally during imaging for unrelated reasons. When symptomatic, they typically present with recurrent UTIs, flank discomfort, bladder stones forming within the ureterocele, or voiding difficulties.

Emergency symptoms requiring immediate attention include high fever with urinary symptoms suggesting pyelonephritis, severe flank pain indicating obstruction, acute urinary retention, and rarely in girls, prolapse of the ureterocele through the urethra.

Causes

A ureterocele develops during fetal development when the ureteral bud, which forms the ureter and collecting system, develops abnormally. The Chwalla membrane, a thin membrane at the ureteral opening, fails to dissolve completely during development. This creates a weakness in the ureteral wall that allows it to balloon outward.

The condition frequently occurs alongside other urinary tract abnormalities. Duplex kidney systems, where two ureters drain the same kidney, are present in about 80% of cases. The upper pole portion of a duplex kidney is often the affected segment. Vesicoureteral reflux, where urine flows backward from the bladder toward the kidney, commonly coexists with ureteroceles. Dysplastic kidney tissue and abnormalities of the opposite kidney may also be present.

Risk factors include female sex, family history of urinary tract abnormalities, and Caucasian ethnicity.

Diagnosis

Prenatal ultrasound may reveal hydronephrosis, a fluid-filled cyst at the bladder base, dilated ureter, or the characteristic appearance of a duplex kidney, prompting further evaluation after birth.

Postnatal ultrasound is the first-line imaging test. It shows the ureterocele as a thin-walled cyst within the bladder, evaluates kidney size and degree of hydronephrosis, and may demonstrate the “drooping lily” sign in duplex kidneys. Ultrasound has the advantage of avoiding radiation exposure.

Voiding cystourethrogram (VCUG) uses X-ray with contrast dye to evaluate for vesicoureteral reflux and is essential for surgical planning. The ureterocele appears as a filling defect in the bladder, often described as having a “cobra head” or “spring onion” appearance.

Nuclear renal scans (DMSA or MAG3) assess kidney function and determine whether the affected kidney portion is working. This information is critical for treatment decisions. MAG3 scans evaluate drainage patterns while DMSA scans detect kidney scarring.

MRI urography provides detailed anatomical assessment without radiation and is useful for complex cases, though young children may require sedation.

Cystoscopy allows direct visualization of the ureterocele and is often combined with endoscopic treatment when intervention is planned.

Treatment

Treatment decisions depend on the type and size of the ureterocele, associated abnormalities, kidney function, and presenting symptoms.

Observation is appropriate for small, asymptomatic intravesical ureteroceles in patients with preserved kidney function and no significant obstruction or reflux. Regular ultrasound monitoring ensures any changes are detected early.

Antibiotic prophylaxis with low-dose antibiotics prevents urinary tract infections and protects kidney function. This may be used as a bridge to surgery, during the observation period, or as part of long-term management.

Endoscopic puncture or incision is a minimally invasive procedure performed through a cystoscope. A small incision is made in the ureterocele to decompress it, relieving obstruction. This approach has high success rates for decompression (85-90%) and is often the first-line treatment, especially in infants. However, the incision may create vesicoureteral reflux in up to 50% of cases, which may require subsequent surgery.

Upper pole nephrectomy (heminephrectomy) removes the non-functioning upper portion of a duplex kidney while preserving the healthy lower pole. This procedure is indicated when the upper pole has minimal or no function and can be performed laparoscopically or robotically.

Ureterocele excision with ureteral reimplantation involves complete removal of the ureterocele and reimplanting the ureters into the bladder using an anti-reflux technique. This definitive approach is indicated for failed endoscopic treatment, significant vesicoureteral reflux, single-system ureteroceles, or complex cases.

For newborns and infants, endoscopic puncture is typically preferred as first-line treatment because it allows the kidneys to mature and function to potentially improve, sometimes avoiding more extensive surgery. Close follow-up remains essential. Older children and adults may tolerate observation if asymptomatic, though definitive surgery is more commonly considered when symptoms develop.

When to See a Doctor

Regular follow-up with a pediatric urologist or urologist is essential for anyone with a ureterocele. Most children require annual ultrasound monitoring even after successful treatment to ensure the condition remains stable.

Contact your doctor promptly if your child develops fever above 38°C (100.4°F), foul-smelling or cloudy urine, pain with urination, unusual fussiness or poor feeding, or flank pain. These symptoms may indicate a urinary tract infection requiring treatment.

Seek emergency care for high fever with shaking chills, severe abdominal or flank pain, inability to urinate, bloody urine with pain, or signs of serious illness such as lethargy or poor responsiveness. Prompt treatment of infections protects kidney function and prevents complications.

The outlook for children with ureterocele is generally good when diagnosed and treated early. Many children have normal kidney function long-term, and about half need only one surgery. Understanding that treatment is usually successful, recognizing UTI symptoms early, following antibiotic prophylaxis if prescribed, and keeping all follow-up appointments are key to optimal outcomes.