Chapter 1 Definition, classification, and embryology

Ureteroceles were described as early at 1834 described as a double bladder, urethral hernia or cystic outpouching located at the distal end of the ureter. Debate exists regarding the embryologic origin of ureteroceles, mainly due to the various types of ureteroceles, suspected to have different embryologic inciting events. Several different ureterocele classifications have been described since their initial reporting. The current most commonly used classification system proposed by the AAP, classifies ureteroceles by location, either intravesical or ectopic. They are further classified by the type of ureteral orifice, namely stenotic, sphincteric or sphincterostenotic. Finally, ureteroceles are classified by the type of collecting system associated with them, either a single system or a duplex system.