The 'septation sign' in multicystic dysplastic kidney

The case report is presented of a neonate with a unilateral multicystic dysplastic kidney. An intravenous pyelogram revealed septations throughout this kidney with late pooling of contrast media within the cystic structures. The pathological data stresses the presence of normal appearing glomeruli interspersed between the dysplastic cystic parenchyma. The possible etiologies for the septation sign and pudding phenomenon are discussed.