Approaches to the treatment of a multisystem form of juvenile xanthogranuloma with central nervous system lesion

Relevance. Juvenile xanthogranuloma (JXG) is the most common form of non-Langerhans cell histiocytic disorder. Cutaneous forms of the disease spontaneously regress within a few years, while systemic forms of JXG require treatment and may pose a threat to the lives of patients. Due to the lack of unified approach to the treatment of multisystem forms of JXG, the question of effective therapy tactics remains unresolved. The most common approach is to use Langerhans cell histiocytosis (LCH) treatment regimens for JXG. With the understanding of the leading role of mutations in the MEK-ERK signaling pathway in the pathogenesis of JXG, targeted therapy, BRAF- and MEK-inhibitors, are increasingly being considered in the treatment of JXG. Clinical cases. We present two cases of multisystem JXG with central nervous system (CNS) lesions. The first patient with CNS and skin lesions was treated with chemotherapy, developed for the treatment of multisystem LCH, which allowed us to obtain an effect “active disease better” (AD better). The second JXG patient with brain, lungs, bones, and adrenal gland lesions, combined targeted therapy with BRAF- and MEKinhibitors, vemurafenib and cobimetinib, resulted in a “non active disease” (NAD) effect. Conclusion. Multisystem form of JXG with CNS involvement is a rare oncological disease, the therapy of which has not been developed. With the introduction of molecular genetic profiling technology, it became possible to obtain NAD effect using targeted therapy.