ABSTRACT
Ureteroceles are congenital, cystic dilations of the terminal, intravesical portion of the ureter. The associated ureteral orifice, often extremely difficult to visualize, may be partially or totally obstructed, resulting in variability in size from small to very large. The pathogenesis of the ureterocele remains unclear, although several theories have sought to explain it. Chwalla and Ericsson attributed the ureterocele formation to the persistence of an epithelial sheet separating the lumen of the distal portion of the Wolffian duct and the urogenital sinus. Ureteroceles can be associated with the ureter draining the upper moiety of a duplex collecting system or with the ureter of a single system. Ureteroceles occur most frequently in females with a 4:1 ratio and are more common in Caucasians. Ureteroceles can be diagnosed in the antenatal period as part of a screening ultrasound. After the 30th week of pregnancy, the ureterocele may be demonstrated in the fetal bladder.
