Fig. 2: Radiological responses over time.

a Axial contrast-enhanced MRI while the patient was on single-agent bevacizumab shows a dural-based frontal lobe metastasis (arrow). b Axial contrast-enhanced image 9 months after radiation therapy shows significant improvement in the irradiated lesion (arrow). c Axial contrast-enhanced MRI 5 months later shows recurrence of the metastasis (arrow). The lesion demonstrates heterogeneous enhancement. d Axial post-contrast MRI 2 months later shows the rapid growth of the cystic lesion (white arrow) and extensive perilesional enhancement (black arrow). e Axial post-contrast image at treatment nadir 2 months after dabrafenib shows a significant decrease in the size of the lesion. f Axial post-contrast image 3 months later shows recurrence of the lesion, this time with solid enhancement (white arrow). The lesion was subsequently resected, showing gliosarcoma.