Follicular cholangitis of the liver masking Langerhans cell histiocytosis

For the first time, the coincidence of follicular cholangitis and hepatic Langerhans cell histiocytosis are described. Hemihepatectomy was performed for suspected malignant stenosis of the left hepatic duct. Histological examination revealed (a) massive intra- and subepithelial proliferations of CD1a- and Langerin-positive Langerhans cells (LC) (b) associated with chronic fibrosing and prominent follicular cholangitis of septal and segmental bile ducts, (c) followed by multifocal LCH with granulomatous or eosinophil-rich bile duct destruction and necrotizing obliteration of the left hepatic duct, and (d) advanced secondary biliary fibrosis originating from peripheral portal fields as a result of bile duct obliteration. The striking colocalization of these findings presume a local antigen activation of LC, as part of the innate immune system, followed by a chronic fibrosing cholangitis with a prominent periductal lymphofollicular reaction. Furthermore, proliferating LC appeared to be the source of a multifocal bile duct-associated LCH with obliteration of the left hepatic bile duct. The absence of systemic foci over the course of a year indicates LCH of hepatic origin, confined to the liver. Cases of rare, eye-catching follicular cholangitis should be analyzed more closely for reactive LC proliferations and possible hepatic LCH.