Bear's paw sign of xanthogranulomatous pyeloneprhitis

Contrast-enhanced computed tomography scan showing an enlarged (12.2 cm × 9.1 cm) left kidney (arrows) with dilated renal pelvis and calyces and a multiloculated appearance. Such an image, which has been compared with the toe pads of a bear's paw, is considered typical of xanthogranulomatous pyelonephritis.