Severe persistent bone marrow failure following therapy with 2‐chlorodeoxyadenosine for relapsing juvenile xanthogranuloma of the brain

2-Chlorodeoxyadenosine (2-CdA) has been successfully used in children to treat refractory Langerhans cell histiocytosis and juvenile xanthogranuloma (JXG) as salvage therapy. Although 2-CdA is generally well-tolerated, with temporary myelosuppression as the primary dose-limiting toxicity, prolonged myelosuppressive, and immunosuppressive effects have been reported. We describe an adolescent patient with refractory multiple central nervous system JXG, with the lesion size markedly reduced after treatment with 2-CdA. However, severe transfusion-dependent bone marrow failure developed after five courses of 2-CdA. He underwent successful bone marrow transplantation from his HLA compatible sister with reduced intensity conditioning.