A ureterocele is a congenital cystic dilation of the distal (terminal) portion of the ureter as it enters the urinary bladder. It forms when the ureteral opening is abnormally narrow, causing the submucosal segment of the ureter to balloon outward into the bladder lumen. On ultrasound, a ureterocele appears as a round, thin-walled, cystic structure protruding into the bladder at the site where the ureter normally inserts. It characteristically expands and collapses with peristaltic waves of urine flow. Ureteroceles are more common in females and are frequently associated with a duplex (duplicated) collecting system. They can cause urinary obstruction, recurrent infections, and vesicoureteral reflux. Prenatal ultrasound may detect ureteroceles as part of the evaluation for fetal hydronephrosis.
Sonography Term