[Isolated retroperitoneal hydatid cyst. Apropos of 2 new cases]

Hydatid disease in endemic countries is common but an isolated retroperitoneal localisation is rare. After a review of the aetiopathogenesis and clinical aspects, the authors express the opinion that safe, rapid and reliable technique of echotomography is the key investigation in obtaining a positive diagnosis. In terms of its course, the histopathological appearances are those of a locally malignant tumour which as a preferential and severe effect on renal function. Surgery is the only valid method for eradication of the parasite and freeing the urinary tract.