[Prenatal diagnosis of bilateral polycystic kidney disease in a twin pregnancy].

Polycystic renal dysplasia is a lethal malformation when it is bilateral. The authors report a rare case of polycystic dysplasia observed in both foetuses of a twin pregnancy, one of whom survived despite bilateral polycystic kidney disease. These biamniotic monoplacental twins were delivered prematurely at 33 weeks of amenorrhoea. The diagnosis was made by antenatal ultrasound. The first twin presented bilateral renal lesions: right polycystic kidney, segmental polycystic dysplasia of the superior pole of the left kidney on a completely duplicated system. The second twin presented a right polycystic kidney. In the light of this case report, the authors describe the various antenatal presentations of polycystic kidney and the associated urological malformations. Involvement of both foetuses of a twin pregnancy raises a discussion of the aetiopathogenesis of polycystic renal dysplasia.