[Basedow's disease in an adolescent with histiocytosis X]. / Maladie de Basedow chez un adolescent porteur d'une histiocytose X.

BACKGROUND: Immunological dysfunction is known to be present in Langerhans cell histiocytosis; some autoimmune diseases with autoantibodies associated with this condition have already been described. This immunological dysfunction could play a role in the Langerhans cell histiocytosis pathogenesis. CASE REPORT: A 13 year-old boy presented a multifocal bone Langerhans cell histiocytosis associated with Graves' syndrome. This last condition was successfully treated with carbimazole while the focal lesions of histiocytosis did not require any treatment. CONCLUSION: This unique association could be explained by the immunological dysfunction seen in Langerhans cell histiocytosis with secondary appearance of thyreo-stimulating antibodies.