[Retro-iliac ureter. Report of a case lumbosacral agenesis].

The authors report a case of retro-iliac ureter associated with a lumbo-sacral agenesis. Retro-iliac ureter seems in relation with abnormal constitution of aortic division and/or ilio-cava confluence when the metanephros migrates. Lumbosacral agenesis is the most severe state of sacral agenesis and is a part of the syndrome of caudal regression. The association of the two malformations have never been described and could be fortuitous. Nevertheless, the vertebral malformation could induce a perturbation in the formation of vascular structures and so an abnormal migration of the metanephros.