9.2.1 Ectopic ureterocele

Ectopic ureterocele is the most common form of ureterocele (> 80%) and occurs bilaterally in about 40% of cases. It is voluminous, dissociating the trigone and slipping into the urethra, and can rarely prolapse through the urethral meatus. The ureterocele orifice is tight, rarely large, located near the bladder neck either in the bladder itself or in the urethra below the bladder neck. The ureter corresponding to the lower pole moiety is raised by the ureterocele and frequently refluxing or compressed by the ureterocele, leading to an obstructive megaureter. A contralateral renal duplication is associated in 50% of cases. Occasionally, very large ureteroceles are responsible for reflux or obstruction of the contralateral upper tract.