Xanthogranulomatous pyelonephritis

Case contributed by Dr Mostafa El-Feky


Right loin pain and fever.

Patient Data

Age: 55 years
Gender: Female

CT abdomen


Obstructing right pelvic stone with associated grade III hydronephrosis and thinned out cortex. There is associated extensive peri-nephric fat stranding and fibro-fatty accumulation. Other small calyceal stones are also noted.

A perinephric abscess with communication with a right psoas muscle and right paraspinal muscle abscesses.

Hypodense non-enhancing irregular shape cystic lesion at the subhepatic region with minimally enhancing wall representative of subhepatic abscess.

Multiple mildly enlarged locoregional lymph nodes. Marked stranding of omental and mesenteric fat planes.

Calculous gallbladder disease.

Case Discussion

CT scan demonstrates an enlarged right kidney with a large pelvic staghorn calculus and chronic grade III hydronephrosis with perirenal fatty proliferation.

The appearance is characteristic of xanthogranulomatous pyelonephritis. Also note the formation of a perirenal abscess that extends to involve the right psoas muscle and subhepatic region.

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