BACKGROUND Langerhans cell histiocytosis (LCH) is defined by the association of a clinical and radiological involvement and a biopsy of a pathological tissue. Extension: it can affect any organ or system of the body but most commonly the bone (80% of cases), the skin (33%) and the pituitary (25%). Other organs are concerned such as liver, spleen, hematopoietic system and the lungs (15% each), lymph nodes (5-10%) and central nervous system (CNS) excluding the pituitary (2-4%). Natural history: the natural history of the disease is very heterogeneous, ranging from auto-regressive lesions to a disease affecting multiple organs with fatal consequences, while some lesions may be responsible for permanent sequels. A multidisciplinary approach: the perception of disease from physicians varies greatly depending on their speciality and experience, as well as the presentation of the disease or the short-term treatment outcomes. But whatever the initial view of the treating physician, a multidisciplinary approach to the LCH is recommended as well as the coordination of the necessary care of this systemic disease and its associated morbidity. METHODS current treatment protocols, adapted to the situation of each patient, provide a survival of 98% in children. The sequels, such as diabetes insipidus, hormonal deficits, deafness and even more rarely respiratory failure and sclerosing cholangitis are seen in up to 30% of children.