Response and progression of ND lesions. (A) Axial MRI images of case 6, with isolated ND-LCH showing significant reduction in T2-hyperintense lesions after treatment with dabrafenib and trametinib. Note that the remaining hyperintense lesion in the right cerebellum at last follow-up (right column; middle image) is related to the biopsy that was taken from this anatomical site. (B) Axial MRI images of case 33 showing the development of T2- and FLAIR-hyperintense lesions in the pons and cerebellum while receiving treatment with vemurafenib. The patient also developed clinical symptoms of neurodegeneration and died 7.5 months after the MRI scan depicting ND lesions was made. ND, neurodegenerative; FLAIR, fluid-attenuated inversion recovery.