Abstract: Objective The aim of this study was to summarize imaging features of xanthogranulomatous cholecystitis (XGC) and its histopathological manifestations. Methods The clinical material of 20 patients with XGC proven by surgery and pathology was retrospectively analyzed, and the imaging incluing CT and MRI, and histopathological features were summarized. Results The CT scan showed that the gallbladder was enlarged in 90.0% of the patients, 100.0% gall bladder thickened, including 35.0% localized and 65.0% diffuse thickening. 20.0% of the patients presented with enhanced intra-gall bladder nodules at the arterial phase and 75.0% with multiple low-density nodules at the venous phase. All patient had cholecystolithiasis. 75.0% of the patients demonstrated unclear gaps between liver and gallbladder. 40.0% of the patients presented with continuous, while 60.0% with interrupted enhancement of gallbladder mucosa line; the MRI indicated the gallbladder enlargement was found in 91.7% of patients, and 100% with the gall bladder wall thickened, among which the localized thickened in 50.0% and the diffuse thickened in 50.0%, presenting with "sandwich biscuit sign"; 100.0% of patients showed multiple abnormal nodular signals in thickened gallbladder wall, and 100.0% with enhanced intra-cystic nodules with low signal at enhanced venous phase. All patients had cholecystolithiasis. The gaps between liver and gallbladder were unclear in 91.7% of patients. 58.3% of patients presented with continuous, while 41.7% with interrupted enhancement of gallbladder mucosa line. 25.0% had reticular changes at mucosal stripping. The histopathological examination showed that fibrosis withinflammatory cell infiltration in gall bladder tissues, and granulomatous formation with abundant foam-like cell gathering at the bladder walls. Conclusion The patients with XGC have a unique imaging features, which might help making a correct pre-operational diagnosis and management.

Key words: Xanthogranulomatous cholecystitis, CT, MRI, Diagnosis