Biliary manifestation of Erdheim-Chester disease mimicking Klatskin's carcinoma.

Erdheim-Chester disease (ECD) is a rare non-Langerhans form of histiocytosis, characterized by infiltration of foamy, lipid-laden histiocytes often affecting the lower extremities and resulting in symmetrical osteosclerosis. Internal organs involved include the lung and the kidneys, reflecting progressive disseminated granulomatous infiltration. Progression may be fatal, especially in cases of systemic extraosseous involvement. Here, we report a patient with elevated serum levels of liver enzymes due to intra- and extrahepatic bile duct stenoses. The patient's past medical history was remarkable for ECD, since 1 yr before he had undergone surgery for a pituitary lesion in our neurosurgical department revealing the typical histological and immunohistochemical criteria of ECD. Because no biliary manifestation of ECD had been described so far in the literature, surgery of suspected bile duct carcinoma was performed unraveling an unresectable tumor of the hilar region. Surprisingly, histologic examination of intraoperative biopsy specimens failed to demonstrate malignancy but rather revealed another xanthogranulomatous lesion embedded in extended periductal fibrosis as is typically described in extrahepatic parenchymal organ manifestation of ECD. Other possible reasons for cholestatic liver disease were excluded. Secondary cholestasis was overcome by endoscopic dilatation and biliary stenting with stents being exchanged every 3 months. During follow-up for 7 yr we have observed only a slight increase of the hilar stenosis so far. This is the first report describing biliary manifestation of ECD. Even though ECD is a rare cause of cholestasis, it should be considered in patients with this disorder in the setting of multiorgan manifestation.