Caecoureterocele and concepts on the embryology and aetiology of ureteroceles.

Caccourcterocele, a bizarre form of vesico-urethral ureterocele, has two characteristics, (1) a wide incompetent orifice in the bladder and (2) a long submucosal tongue which extends along the female urethra deep to the mucosal lining of the urethra. The peculiar configuration of this ureterocele is not readily explained on the basis of obstruction, but rather on embryological grounds. The situation of the incompetent orifice in the bladder and the reflux of urine into the tongue in the urethra add a urethral obstructive component which induces urological damage. The Mullerian duct migration is responsible not only for the transposition of the orifices of some ectopic ureters from the trigone to the distal half of the female urethra, the urethrovaginal bridge and the hymen of the vagina, but also for the urethral extension of the caecoureterocele, which is “tongue-tied” to the Mullerian ducts in their descent to the exterior. All other ureteroceles with “giant” orifices are likewise developmental in origin, though in many an obstructive component is superadded by virtue of the location of the orifice within the grasp of the internal sphincter of the urethra.