The paper describes an unusual angiographic pattern within the context of stenosis of the pyeloureteral union and giant hydronephrosis of the adult, with a presumed congenital origin. From the embryonic point of view we discuss the remote possibility of this being a real "agenesis" of the renal artery with no agenesis of the kidney, irrigated by multiple segmental arteries following the characteristic metamerism of the mesonephros. On the other hand, it seems more consistent to explain such vascular pattern as an image of severe atrophy, in correlation with the hydronephrosis advanced stage, and not as a primary congenital defect. However, the interaction of both factors (congenital-malformative and acquired-involutive) could be more overlapped than what initially appears to be.