[Unilateral multicystic dysplastic kidney and contralateral megacalycosis. An unusual association].

Dilation of the genitourinary tract is not always synonymous with obstruction. It is well known that malformations with apparent hydronephrosis and normal urinary flow can exist. In addition, two or more distinct malformations of the genitourinary tract can coexist in the same patient. We present a case of coexistence of a unilateral multicystic dysplastic kidney and contralateral megacalycosis associated with ipsilateral distal segmental megaureter. This association is unusual in the literature. Glomerular renal function was normal, with only a slight defect of renal concentration capacity.