Combined treatment with vemurafenib and cobimetinib in Langerhans cell histiocytosis and Erdheim-Chester disease overlap syndrome: A case Report

Histiocytoses are clonal disorders diseases derived from the monocyte-macrophage lineage. The Erdheim–Chester Disease (ECD) and Langerhans Cell Histiocytosis (LCH) may occur in association with overlapping clinical, histopathological molecular features, harboring somatic MAP2K1 mutations more than 50% of patients. BRAF MEK inhibitors have shown to be efficacious ECD LCH, including responses patients CNS involvement. This case report describes a 59-year-old woman who presented vemurafenib-refractory ECD/LCH overlap syndrome treated vemurafenib/cobimetinib dual therapy, rapidly progressing neurological involvement after its initiation. Although targeted therapy plays crucial role treatment histiocytosis, only anecdotal clinical cases been reported or LCH collaborative trials needed improve outcomes.