Diagnosis

Xanthogranulomatous cholecystitis

Findings

Contrasted CT images demonstrate a multiseptated gallbladder mass with thick, enhancing septa. The cystic portions of the mass appear to be located within a thickened gallbladder wall. The mass is inseparable from the liver with no biliary ductal dilatation. No calcified gallstones are seen. A small amount of inflammatory stranding surrounds the gallbladder.

T2-weighted and T1-weighted pre and post contrast MRI images demonstrate a thickened gallbladder wall with numerous large intramural cysts. There is a large obstructing gallstone within the neck of the gallbladder. Numerous fluid-fluid levels are present within the wall of the gallbladder. The septated gallbladder wall enhances throughout.

Discussion

Xanthogranulomatous cholecystitis is a rare diagnosis characterized by chronic gallbladder infection with intramural infiltrates of foamy histiocytes and lipid-laden granulomas, similar in etiology to the better known xanthogranulomatous pyelonephritis. Gallstones are thought to obstruct the cystic duct and a mural injury results in macrophage activation with phagocytosis of bile lipids and cholesterol, leading to lipogranuloma formation. It is a condition which occurs predominantly in women between the ages of 60 and 70. Patients usually present with right upper quadrant abdominal pain, fever, and possibly an elevated white blood cell count. Symptoms are often chronic, spanning years. Occasionally the resultant gallbladder mass will result in extrinsic obstruction of the biliary tree resulting in elevation of bilirubin and alkaline phosphatase.

Ultrasound is often the first modality ordered for right upper quadrant pain. Ultrasound imaging findings suggestive of xanthogranulomatous cholecystitis include the presence of gallstones, an asymmetrically thickened gallbladder wall, and a hypoechoic stripe or nodules within the wall of the gallbladder. CT demonstrates the same imaging findings and may better show the hypodense intramural nodules. CT may also show reactive hyperemia within the gallbladder fossa, but as in this case will often not demonstrate the gallstone. The case shown above demonstrates such severe thickening and cystic replacement of the gallbladder wall that identification of the wall is difficult. In this case MRI was ordered for surgical planning and demonstrates the intramural areas of foamy cell proliferation as T2-hyperintense regions. Inflammation within the adjacent liver parenchyma, the enhancing gallbladder wall, and the obstructing gallstones are all well demonstrated on the MRI examination.

Treatment consists of surgical resection for symptomatic relief and to prevent complications such as abscess formation and fistulization with adjacent organs such as the colon and duodenum.

1. Parra JA et al. Xanthogranulomatous Cholecystitits: Clinical, Sonographic and CT Findings in 26 Patients. AJR. 2000;174(4): 979-83.
2. Uchiyama K et al. Xanthogranulomatous Cholecysititis: The Use of Preoperative CT Findings to Differentiate it from Gallbladder Carcinoma. Journal of Hepatobiliary and Pacreatic Surgery. 2009; 16(3):333-38.
3. Chun KA et al. Xanthogranulomatous Cholecystitis: CT Features with Emphasis on Diffferentiation from Gallbladder Carcinoma. Radiology. 1997;203(1): 93-97.