[Langerhans cell histiocytosis].

Histiocytoses originate from the proliferation of mononuclear phagocytes in different tissues. These entities make up a heterogeneous group, and are mainly classified as Langerhans cell histiocytoses and non-Langerhans cell histiocytoses. Langerhans cell histiocytoses have as a common characteristic the proliferation of dendritic antigen-presenting cells with phenotypical and ultrastructural characteristics of Langerhans cells. Infiltration may be limited to one organ, or may be disseminated. The prognosis and the treatment especially depend on the age of the patient and the number and dysfunction of the organs involved. Its etiopathogenesis is unknown, although most researchers currently believe that an alteration in the regulation of the immunological system occurs in these patients.