In this condition the distal ureter balloons at its opening into the bladder, forming a sac-like pouch.

Simple ureterocele, where the condition involves only a single ureter, represents only twenty percent of cases.

The pediatric and adult conditions are often found incidentally, i.e., through diagnostic imaging performed for unrelated reasons.

Redundant collection systems are usually smaller in diameter than single, and predispose the patient to impassable kidney stones.

Cystoscopy-shows translucent cyst which is thin walled surrounding ureteric orifice[citation needed]