Bilateral perirenal urinoma with mediastinal extension.

We report a unique case of adult-type polycystic kidney disease (PKD) having bilateral chronic perirenal fluid collection with unusual extension. Fluid collections at both sides are connected across the midline anterior to the abdominal aorta and inferior vena cava. In addition, supradiaphragmatic extension through aortic hiatus was well demonstrated by computed tomography (CT). Antomical boundaries and relations between two perirenal spaces are evaluated.