Failure of salvage vemurafenib therapy for refractory multisystem Langerhans cell histiocytosis with BRAF-V600E mutation

Background: Langerhans cell histiocytosis (LCH) has been defined as a disorder driven by misguided myeloid differentiation, with up to 50% of cases harboring the BRAF-V600E mutation. Salvage treatment with LCH refractory to vinblastine and steroid regimen is intractable. Vemurafenib is safe and effective in children with refractory BRAF-V600E -positive LCH, but the disease always reactivates with the withdrawal of vemurafenib. Case presentation: Here, we report the first case of BRAF-V600E positive LCH resistant to vemurafenib therapy but effectively salvaged by cytarabine-based chemotherapy. Conclusions Our case report shows that vemurafenib monotherapy might not be effective for every BRAF-V600E -positive refractory LCH, and cytarabine-based chemotherapy might still be a cost-effective therapeutic alternative. Keywords: Langerhans cell histiocytosis, BRAF-V600E mutation, Vemurafenib, Chemotherapy