PMC8440069_01
(a) Postcontrast CT images showed hypoperfusion of the left kidney with thinning of the cortex; dilatation of the left kidney excretory system with a "bear's paw sign" is also depicted suggesting diagnosis of xanthogranulomatous pyelonephritis (arrow); (b) postcontrast coronal reconstruction demonstrated ureteral stone (arrowhead) in the distal tract of the left ureter without significant dilatation of the proximal tract; (c) oblique projection pyelography after puncture of the inferior calix of the left kidney demonstrated leakage of contrast media with a double fistulous path form the pelvis directed anteriorly to the left colon (arrow) and posteriorly to the collection in the retroperitoneal collection (arrowhead).
CRIN2021-3604017.001.jpg
PMC8440069_01_CRIN2021-3604017.001.jpg
fig1
After a multidisciplinary team meeting in the emergency area, the patient underwent an interventional radiologic procedure consisting of caval filter placement, left nephrostomy, and percutaneous drainage of the perinephric abscess; during the radiological procedure, contrast injected via the percutaneous drainage revealed a communication between the abscess, the lower pole calyx, and the descending colon (Figure 1(c)).
(a) H & E 4x: acute pyelonephritis, with abscessualization of the calices and pelvis and xanthogranulomatous chronic inflammation; (b) H & E 10x: detailed image of the typical multinucleated giant cells in the context of XGPN.
CRIN2021-3604017.002.jpg
PMC8440069_01_CRIN2021-3604017.002.jpg
fig2
Histopathological examination of the kidney showed an intense and widespread acute pyelonephritis, with abscessualization of the calices and pelvis and xanthogranulomatous chronic inflammation, with multinucleated giant cells, lipid-laden macrophages, and acute inflammatory cells, as well as loose "xanthoma" cells (Figure 2).