A 47-year-old man presented with sudden visual loss, optic disk edema, retinal ischemia, and limited upgaze in the left eye. Initial MRI revealed thickened, enhancing left optic nerve. Extensive work-up for an inflammatory and infiltrative etiology was positive only for Borrelia burgdorferi IgM by Western blot. Six weeks later the patient had numbness and weakness on his left side. MRI showed enhancing lesions extending from the left optic nerve to the optic chiasm, along the visual pathways bilaterally, mainly on the right side from optic tract to lateral geniculate body and pulvinar. Stereotactic biopsy of the right pulvinar lesion revealed glioblastoma. The tumor progressed rapidly, and the patient died 11 weeks after the onset of first symptoms. (C) 2014 Elsevier Inc. All rights reserved.