A newborn female was found to have a quadruplication of the ureter: four pr
oximal, slim ureters opened into a large ureteral cyst and a distal monoure
ter opened into the bladder. Only five cases of ureteral quadruplication ha
ve been reported in the literature, one of which presented with identical p
athology. These two cases may have been caused by similar, unidentified abn
ormal embryonic development.