[Cystic pyeloureteritis. Apropos of 40 cases].

A series of 40 cases of cystic pyeloureteritis (CPU) is reported, this affection being considered as rare since only about 150 cases have been described in the literature. The lesion is probably more prevalent than was once believed but many cases probably remain unrecognized because of the paucity of radiologic signs. Based on findings in these 40 patients, results of radiologic imaging are described, the technical precautions needed for its detection emphasized and differential diagnoses discussed, none of which presents insurmountable obstacles since these are more theoretical than real. Pathogenesis is thought to be an acquired particular form of urinary mucosa metaplasia associated with urinary tract lesions responsible for stasis or chronic inflammation. Treatment should be conservative because of the usual benign nature of the lesion, although exceptional but possible occlusion by the lesions necessitates a certain surveillance.