XANTHOGRANULOMATOUS CHOLECYSTITIS - CT FEATURES WITH EMPHASIS ON DIFFERENTIATION FROM GALLBLADDER CARCINOMA

PURPOSE: To evaluate the computed tomographic (CT) features of xanthog ranulomatous cholecystitis (XGC) and to distinguish it from gallbladde r carcinoma. MATERIALS AND METHODS: Retrospective analysis was perform ed in 11 patients with XGC and 17 patients with gallbladder carcinoma in which the wall was thickened. The following CT features were analyz ed: maximum wall thickness, intramural hypoattenuated nodules, mucosal line, patterns of wall thickening and enhancement, and the presence o f stones. The changes outside the gallbladder were also compared. RESU LTS: The mean thickness of the gallbladder wall was 1.8 cm in patients with XGC and 2.1 cm in patients with gallbladder carcinoma. Intramura l hypoattenuated nodules were seen in all patients with XGC but in onl y seven patients with gallbladder carcinoma (P = .008). The mucosal li ne was observed in nine patients with XGC and in six with gallbladder carcinoma (P = .02). The gallbladder wall was more diffusely thickened in patients with XGC (10 of 11 patients) than in patients with gallbl adder carcinoma (seven of 17 patients) (P = .01). The occurrence of ch anges outside the gallbladder did not differ statistically significant ly. CONCLUSION: Because of a statistically significant overlap of CT f eatures, only when intramural hypoattenuated nodules occupy a large ar ea of the thickened gallbladder wall can the diagnosis of XGC be highl y suggestive. The diagnosis of XGC at CT may indicate a less aggressiv e surgical approach.