Langerhans' cell granuloma confined to the bile duct.

Langerhans' cell histiocytosis (LCH) of the liver is uncommon. When seen, it is part of multifocal disease and can present as biliary obstruction. We present a case of sclerosing biliary disease with a solitary LCH lesion and no evidence of systemic disease. We postulate that the LCH is a secondary phenomenon, arising against a background of a complex, familial liver disease. This case also raises the possibility that some instances of idiopathic sclerosing cholangitis may follow cryptic LCH of the bile ducts.