Eosinophilic cholangitis: a case of 'malignant masquerade'.

BACKGROUND: A variety of causes of inflammatory bile duct stricture can masquerade as hilar cholangiocarcinoma. Eosinophilic cholangitis is a further example. CASE OUTLINE: A 50-year-old woman with epigastric pain and deranged liver function was found to have a stricture of the common hepatic duct on ERCP with an associated mass on MRl.The lesion was excised with reconstruction of the right and left hepatic ducts, and the patient recovered well. Histopathological examination of the resected gallbladder and bile duct showed diffuse inflammation with a predominant eosinophil infiltrate.The presence of Candida albicans in the bile duct lumen can probably be attributed to the preoperative biliary stent.There was a modest postoperative rise in peripheral eosinophil count. DISCUSSION: A literature search reveals only six previous cases of eosinophilic cholangitis, but similar infiltrates have also been seen in occasional cholecystectomy specimens. As the present patient did not have gallstones, the aetiology remains unclear. Peripheral eosinophilia is an unreliable clue to the diagnosis, which is usually likely to escape detection until the biliary stricture has been resected.