[Preoperative diagnosis of xanthogranulomatous cholecystitis].

Xanthogranulomatous cholecystitis (XGC) is a benign chronic inflammation of the gallbladder, rarely described in the radiologic literature. Like xanthogranulomatous pyelonephritis, it can clinically and radiologically mimic carcinoma. This unusual entity is characterized morphologically 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 fibrosis into surrounding tissues. It is clear that recurrent inflammation and calculi are important for the pathogenesis, which is not well understood. The clinical presentation and radiologic findings of XGC are non specific. Irregular thickening of the gallbladder wall and local extension of the process can mimic carcinoma. Diagnosis of XGC is always established by histological examination, characterized by the infiltration of round cells, lipid laden histocytes and multinucleated giant cells in the muscle layer. We report a case of 76-year-old woman who had an episode of epigastric and right upper quadrant pain, 4 months before admission. Physical examination demonstrated a palpable mass in gallbladder region. Echography and computed tomography showed a large gallbladder, a thickened wall and an infiltration of the adjacent liver. The relatively well defined gallbladder internal border and the absence of biliary tract's dilatation allowed us to suggest the diagnosis of XGC, which was confirmed intraoperatively by frozen section histology. Once the diagnosis was established, cholecystectomy was performed. Occasionally, the inflammatory reaction is so severe that a subtotal cholecystectomy is required. Postoperative recovery was, as usually, uneventful. Although a rare entity, XGC should be considered in the differential diagnosis of complex right upper quadrant masses, as well as neoplastic gallbladder disease.