(A) Contrast-enhanced computed tomography (CT) image in nephrographic phase at the level of the kidneys shows a cystic-appearing lesion (arrow) within the left kidney. There is no obvious enhancing soft tissue. Fine septa (arrowheads) are visible in the lesion. (B) Contrast-enhanced CT in excretory phase at a level lower than that in Figure A shows herniation of the cystic lesion (arrow) into the opacified renal pelvis (arrowhead).