Group of disorders of histiocyte proliferation which includes letterer-siwe disease; hand-schueller-christian syndrome; and eosinophilic granuloma; langerhans cells are components of the lesions.

Langerhans cell histiocytosis (LCH) is an abnormal clonal proliferation of Langerhans cells, abnormal cells deriving from bone marrow and capable of migrating from skin to lymph nodes. Symptoms range from isolated bone lesions to multisystem disease. LCH is part of a group of syndromes called histiocytoses, which are characterized by an abnormal proliferation of histiocytes (an archaic term for activated dendritic cells and macrophages)...