[Child Langerhans cell histiocytosis].

DEFINITION: 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.

THERAPY: 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.