Xanthogranulomatous choledochitis: a previously undescribed mass lesion of the hepatobiliary and ampullary region.

Solid liver and pancreatic masses are commonly neoplastic in nature; however, inflammatory lesions mimicking carcinoma are at times encountered in these sites. We report two cases of previously undescribed inflammatory mass lesions of the liver and pancreas that originated in the biliary tract. Detailed clinical and histologic evaluations were performed in two patients who underwent right partial hepatic lobectomy and Whipple's resection for presumed hepatic and pancreatic neoplasms. In case 1, with a remote history of cholecystectomy and recent extraction of a stone from the common bile duct, a liver mass in segment 6 was discovered incidentally. In case 2, a periampullary pancreatic mass was diagnosed radiographically following papillotomy and stent insertion for stricture and biliary calculous disease. The histologic findings in both cases were similar, localized around a part of the biliary tract, and consisted of inspissated bile, acute and chronic inflammation, abundant lipid-laden macrophages, fibrosis, and giant cell reaction. No neoplasm was identified. On the basis of the close resemblance of these features to those seen in xanthogranulomatous cholecystitis, the lesions seen here were termed xanthogranulomatous choledochitis. In conclusion, xanthogranulomatous choledochitis is a benign inflammatory process involving the biliary tract that can form a mass lesion within the liver or pancreas and thus mimic a neoplasm. Extensive sampling of the lesion is required to rule out an underlying neoplastic process. In our patients a propensity to form lithogenic bile and a prior history of biliary tract operative procedure were present.