NT-34COMPLETE RESPONSE TO VEMURAFINIB IN A PATIENT WITH METASTATIC ANAPLASTIC XANTHROASTROCYTOMA

INTRODUCTION: Approximately 70% of pleomorphic xanthroastrocytomas(PXA) harbor the BRAF-V600E mutation.Vemurafinib has demonstrated activity in melanoma patients with the mutation, but variable activity in other tumors. We report complete response to vemurafanib in a patient with metastatic, anaplastic PXA. CASE: A 38 year old man presented with four weeks of visual disturbance. He underwent complete resection of a left occipital anaplastic PXA, BRAF-V600E mutated. Re-resection was performed one month later for local recurrence with new dural-based disease. Concern for leptomeningeal disease prompted cranio-spinal irradiation. Mid-treatment MRI demonstrated in-field growth of dural nodules and bony invasion. Simultaneously, he developed dyspnea due to bilateral pleural effusions and lung nodules. Biopsy of nodules and effusion revealed a BRAF-V600E mutated neoplasm, confirming metastatic disease. Vemurafinib was initiated, with almost immediate relief of dyspnea. Now, three months later, the patient has no detectable disease. DISCUSSION: Though the response to vemurafinib in primary CNS neoplasms has been modest, this case suggests rapid and complete response is possible. It also supports the argument for early BRAF-V600E testing in glial tumors.