<prompt> adder head appearance on excretory urography is seen inHydronephrosisInfantile polycystic kidneyUreteroceleHorseshoe kidney  <response>: Ureterocele 1310-LB 1290-B L 25thUreterocele is a cystic enlargement of the intramural portion of the ureter thought to result from congenital atresia of the ureteric orifice. The adder-head on excretory urography is typical Usually the cyst wall is composed of urothelium only and the diagnosis is confirmed by the cystoscopic appearance of a translucent cyst enlarging and collapsing as urine flows in from the upper ureter. 