Jul 10, 2024 · The bear paw sign refers to the cross-sectional appearance of the kidney affected by xanthogranulomatous pyelonephritis. There is a radial arrangement of multiple, low attenuation rounded spaces representing dilated calyces, surrounded by thin renal parenchyma that has higher attenuation or contrast enhancement, mimicking the appearance of the ...

Feb 8, 2025 · CT findings are most helpful in reaching the correct diagnosis. The normal renal outline is lost and enlarged with a paradoxical contracted renal pelvis. The calyces, in contrast, are dilated giving a multiloculated appearance that has been likened to the paw print of a bear (bear's paw sign) 3.

We herein report the case of a 44-year-old woman, with a history of left kidney staghorn calculi and recurrent urinary tract infections. Abdominal computed tomography showed the ‘bear paw’ sign, typical appearance of XGP and patient underwent a nephrectomy with uneventful post-operative course.

The pathognomonic CT aspect is called the "paw sign" and it is characterized by hypoattenuating masses arranged in a “hydronephrotic” pattern, which replaces the renal parenchyma and enhancement in the margins of these masses after contrast material administration [10].

4 days ago · Bear Paw Sign. Axial, enhanced CT of the right kidney displays a pattern of large "hydronephrotic" collections in the regions of the calyces in the shape of a bear's paw. The renal pelvis is not dilated. The sign is associated with xanthogranulomatous pyelonephritis.

Aug 3, 2022 · The bear paw sign is a radiologic sign seen on computed tomography (CT) that indicates the development of xanthogranulomatous pyelonephritis (XGP). It refers to the multiple, rim-enhancing, low attenuation renal collections seen in the diffuse form of XGP.

We retrospectively reviewed the CT images of 5 patients explored in our department with histopathological confirmed diffuse xanthogranulomatous pyelonephritis diagnostic and the presence of the positive "bear paw sign".

Apr 22, 2023 · The image of a kidney resembles the appearance of the dark toe pads on a polar bear’s paw (↑). The term bear paw sign was proposed by Parker and Clark in 1989 [1]. This is a classic finding in xanthogranulomatous pyelonephritis, but it has also been described in congenital obstruction of the ureteropelvic junction.

Computed tomography of the abdomen and pelvis revealed xanthogranulomatous pyelonephritis with perinephric extension. The bear's paw sign was visualized. The classic radiology triad (unilateral large kidney, renal pelvis stone, and a nonfunctioning or poorly functioning kidney) was also found on computed tomographic imaging.

Aug 1, 2015 · The most commonly described radiologic appearance is the “bear paw” sign, which is due to the presence of multiple, hypoechoic areas of the dilated collecting system with pus and debris that is surrounded by an enhanced rim of contrast medium [28,43,44].