XANTHOGRANULOMATOUS CHOLECYSTITIS MIMICKI NG CARCINOMA OF THE GALLBLADDER - ULTRASOUND AND CT FINDINGS

Xanthogranulomatous cholecystitis (XGC) is a benign chronic inflammati on of the gallbladder, rarely described in the radiologic literature. Like xanthogranulomatous pyelonephritis, it can clinically and radiolo gically mimic carcinoma. This unusual entity is characterized morpholo gically by a broad spectrum of xanthogranulomatous changes seen from a small limited focus within yellow nodule in the gallbladder wall, to diffuse involvement of the entire gallbladder with extension of the fi brosis into surrounding tissues. It is clear that recurrent inflammati on and calculi are important for the pathogenesis, which is not well u nderstood. The clinical presentation and radiologic findings of XGC ar e non specific. Irregular thickening of the gallbladder wall and local extension of the process can mimic carcinoma. Diagnosis of XGC is alw ays established by histological examination, characterized by the infi ltration of round cells, lipid laden histiocytes and multinucleated gi ant cells in the muscle layer. We report a case of 76-year-old woman w ho had an episode of epigastric and right upper quadrant pain, 4 month s before admission. Physical examination demonstrated a palpable mass in gallbladder region. Echography and computed tomography showed a lar ge gallbladder, a thickened wall and an infiltration of the adjacent l iver. The relatively well defined gallbladder internal border and the absence of biliary tract's dilatation allowed us to suggest the diagno sis of XGC, which was confirmed intraoperatively by frozen section his tology. Once the diagnosis was established, cholecystectomy was perfor med. Occasionnally, the inflammatory reaction is so severe that a subt otal cholecystectomy is required. Postoperative recovery was, as usual ly, uneventful. Although a rare entity, XGC should be considered in th e differential diagnosis of complex right upper quadrant masses, as we ll as neoplastic gallbladder disease.