Cases

***** ANSWER *****

Xanthogranulomatous cholecystitis (XGC): XGC is a rare inflammatory disease of the gallbladder found in 1-8% of all postcholecystectomy surgical specimens. The condition predominantly occurs in women aged 60-70 years, and it has a definite predominance in certain geographic areas (eg, India). Approximately 75% of patients with XGC present with clinical features consistent with chronic cholecystitis or biliary colic, including chronic right upper quadrant pain, nausea, and vomiting. The physical findings feature right upper quadrant tenderness to palpation. The importance of this diagnosis is that XGC is a benign condition often mistaken for malignant carcinoma of the gallbladder. XGC is associated with gallbladder carcinoma in 11% of patients. Patients with XGC often undergo excessive surgical resection because of difficulty in distinguishing XGC from gallbladder cancer. Some regard XGC as a variant of chronic cholecystitis, but others consider it a distinct clinical entity because of its active, destructive course characterized by a tendency to form fistulas to neighboring structures (eg, duodenum, liver, colon, skin). Complications such as adhesions to surrounding organs, formation of strictures and fistulas of the biliary duct, gallbladder perforation, and ascending cholangitis are more common in XGC than in infectious cholecystosis. The etiology is rupture of occluded Rokitansky-Aschoff sinuses in the gallbladder wall. This rupture leads to extravasation of inspissated bile and mucin into the gallbladder wall and to the development of grayish yellow nodules or streaks in the wall. The presence of bile in the gallbladder wall induces an inflammatory response, attracting histiocytes and fibroblasts to phagocytose the insoluble cholesterol and phospholipids in the bile. XGC has been likened to xanthogranulomatous pyelonephritis (XGP), a similar process that occurs in the kidney as a result of chronic obstruction of normal urinary outflow by renal calculi. Histologic examination reveals a mixture of ceroid xanthogranuloma with foamy histiocytes, multinucleated foreign-body giant cells, lymphocytes, and fibroblasts. Some investigators have also attributed the condition in part to a delayed hypersensitivity reaction and a subacute form of a bacterial infection (eg, with organisms such as Klebsiella, Escherichia coli, Proteus mirabilis, Enterobacter species, and Citrobacter species). Although XGC has well-defined histologic features, it remains a difficult diagnosis for the treating clinician and radiologist because the features on common diagnostic modalities (eg, US, CT) are often nonspecific. Specifically, sonograms may demonstrate marked (>3 mm) thickening of the wall with many circular, focal, hypoechoic intramural shadows. Endoscopic US may improve the sensitivity for locating intramural lesions. CT can be performed when US results are equivocal to help in differentiating chronic inflammation from gallbladder carcinoma or to look for areas of hypoattenuation in the gallbladder wall. On US and CT, XGC can be identified by gallstones (always seen), marked thickening of the gallbladder wall, inflammatory changes in the contiguous hepatic parenchyma, and fistulous tracts that may form between adjacent organs or the skin (see Images 1-2). MRI, endoscopic retrograde cholangiopancreatography, and fine-needle aspiration cytology are other, sophisticated imaging and diagnostic options available for preoperative management. The diagnosis is often not confirmed until histopathologic frozen sectioning is done. The patient in this case underwent cholecystectomy. Fistulous tracts to organs around the gallbladder had not developed at the time of surgery, and adhesions surrounding the gallbladder were carefully removed. The pathology report was negative for malignancy after the entire specimen was sectioned. The patient was discharged home in good health after he recovered from surgery.