A male teenager from Guinea-Bissau, in Portugal for 15 days, presented with a two-month history of progressive headache, decreased vision and left hemiparesis. On neurological examination, the left eye was inwardly and downwardly deviated, with limited abduction and elevation, and predominantly distal left hemiparesis was noted. His gait was mildly ataxic with spastic circumduction of his left leg. Brain MRI (figure 1) showed multiple areas of fluid-attenuated inversion recovery (FLAIR) …