Xanthogranulomatous cholecystitis: What every radiologist should know.

Xanthogranulomatous cholecystitis (XGC) is an uncommon variant of chronic cholecystitis characterized by xanthogranulomatous inflammation of the gallbladder. Intramural accumulation of lipid-laden macrophages and acute and chronic inflammatory cells is the hallmark of the disease. The xanthogranulomatous inflammation of the gallbladder can be very severe and can spill over to the neighbouring structures like liver, bowel and stomach resulting in dense adhesions, perforation, abscess formation, fistulous communication with adjacent bowel. Striking gallbladder wall thickening and dense local adhesions can be easily mistaken for carcinoma of the gallbladder, both intraoperatively as well as on preoperative imaging. Besides, cases of concomitant gallbladder carcinoma complicating XGC have also been reported in literature. So, we have done a review of the imaging features of XGC in order to better understand the entity as well as to increase the diagnostic yield of the disease summarizing the characteristic imaging findings and associations of XGC. Among other findings, presence of intramural hypodense nodules is considered diagnostic of this entity. However, in some cases, an imaging diagnosis of XGC is virtually impossible. Fine needle aspiration cytology might be handy in such patients. A preoperative counselling should include possibility of differential diagnosis of gallbladder cancer in not so characteristic cases.