A 40-year-old woman with no significant previous medical history presented with a three month history of ataxia, confusion, memory difficulties, and headaches. Physical examination revealed numbness in the left hand, but was otherwise unremarkable. Magnetic resonance imaging fluid-attenuated inversion recovery (MRI FLAIR) images demonstrated multiple small white matter hyperintensities, including lesions involving the corpus callosum. There were also deep gray nuclei lesions (Figure 1). The corpus callosum lesions involved the central fibers (Figure 2). Post gadolinium T1 images demonstrated enhancement of some of the lesions as well as extensive perivascular and leptomeningeal enhancement (Figure 3). Extensive infectious serology, autoimmune panel, and paraneoplastic antibodies were negative. Lumbar puncture revealed elevated protein (1116 mg/L), but was otherwise normal. Brain biopsy indicated no apparent pathology. The patient was tentatively diagnosed with acute encephalopathy and treated with high dose steroids seven days after presentation. She was subsequently discharged and was sent for rehabilitation.