Erdheim-Chester disease associated with an aggressive form of sclerosing cholangitis

Abstract Background Erdheim-Chester disease (ECD) is a rare histiocytic disorder recently recognized as neoplasm due to the discovery of activating MAPK pathway mutations. Hepatic involvement by ECD extremely rare. Case presentation We describe case 64-year-old male who presented with pruritis, weight loss, and cholestatic liver function tests. Magnetic resonance imaging abdomen showed beaded appearance intrahepatic biliary tree. A biopsy was suggestive primary or secondary sclerosing cholangitis. Computerized tomography (CT) perinephric periaortic soft tissue stranding ECD. 18 F-fluorodeoxyglucose positron emission/computerized scan mediastinal hilar mass which turned out be follicular lymphoma. Histopathology molluscum-like skin lesions CD68 + , Factor XIIIa CD1a-foamy histiocytes multiple giant cells The patient developed recurrent episodes ascending cholangitis his hyperbilirubinemia continued worsen despite stenting common hepatic duct stricture found on endoscopic retrograde cholangiopancreatography. Conclusions absence associated inflammatory bowel anti-neutrophil cytoplasmic antibody, well rapidity progression, makes us consider possibility an overlap syndrome. want highlight that negative histopathology should not delay diagnosis effective potentially lifesaving therapies BRAF MEK inhibitors are now available for these patients.