1. EPIDEMIOLOGY — The prevalence of xanthogranulomatous cholecystitis among patients with symptomatic gallbladder disease ranges from 0.7 percent in the United States to up to 10 percent in India and Japan [4-8]. The mean age at presentation varies in different studies from 44 to 63 years [4,9]. A study from India reported a 1:9 male to female ratio [4], while in other reports the male to female ratio ranged from 2:1 to 1:2 [3,7,9].

2. INTRODUCTION — Xanthogranulomatous cholecystitis is a rare inflammatory disease of the gallbladder characterized by a focal or diffuse destructive inflammatory process, with accumulation of lipid laden macrophages, fibrous tissue, and acute and chronic inflammatory cells [1]. In 1970, it was known by the descriptive term fibroxanthogranulomatous cholecystitis [2], but in 1981 the name xanthogranulomatous cholecystitis was proposed in a review of 40 cases from the Armed Forces Institute of Pathology [3]. Its importance lies in the fact that it is a benign condition that may be confused with carcinoma of the gallbladder, which is associated with a poor prognosis.

3. Xanthogranulomatous cholecystitis was initially described as a variant of chronic cholecystitis. However, while the latter is usually regarded as a benign condition with questionable clinical significance, xanthogranulomatous cholecystitis is an active and destructive process that can lead to significant morbidity as the inflammatory process usually extends into the gallbladder wall and adjacent structures. Thus, it should be considered a distinct clinical entity.

4. PATHOGENESIS — The pathogenesis of xanthogranulomatous cholecystitis is thought to be related to extravasation of bile into the gallbladder wall from rupture of Rokitansky-Aschoff sinuses or by mucosal ulceration [3,10]. This event incites an inflammatory reaction in the interstitial tissue, whereby fibroblasts and macrophages phagocytose the biliary lipids in bile, such as cholesterol and phospholipids leading to the formation of xanthoma cells.

5. Gallstones may have an important role in the pathogenesis, since they appear to be present in all patients . It has been suggested that xanthogranulomatous cholecystitis is analogous to xanthogranulomatous pyelonephritis, which results from obstruction and stasis due to renal calculi

6. PATHOLOGY — On gross examination, the gallbladder is thickened and the serosa is covered with dense fibrous adhesions .The mucosal surface may be ulcerated and cross sections through the wall reveal xanthogranulomatous foci, which appear as yellow nodules or plaques. These yellowish foci may extend into adjacent structures, such as the liver, duodenum, transverse colon, and omentum].

7. Microscopically, the xanthogranulomatous foci are composed of abundant lipid laden macrophages, fibroblasts, and inflammatory cells . The lipid laden macrophages are of two morphological types: rounded foamy macrophages and spindle-shaped cells with more granular cytoplasm and elongated nuclei. Other findings include the presence of cholesterol clefts, lipid droplets, hemosiderin deposits, and extravasated bile.

8. The relationship between xanthogranulomatous cholecystitis and gallbladder carcinoma is uncertain. Focal granulomatous changes were seen deep within the gallbladder wall in association with neoplastic invasion in a study of five patients, suggesting a possible relationship between both entities [13]. Another study found adenocarcinoma in nearly 10 percent of resected specimens of xanthogranulomatous cholecystitis [9], while in a larger study no such relationship was observed [4].