Fig. 2.

Display of demyelinating lesions evolution over 6 months. Successive brain MRI are displayed on axial T2-weighted images (top row), axial (middle row) and sagittal (bottom row) T1-weighted images after i.v. infusion of gadolinium contrast media. a Baseline in April 2018 before CNS demyelination. b Demyelinating lesions were diagnosed in June 2018. The largest lesion was located in the juxtacortical white matter of the left superior frontal gyrus (arrows) while numerous small ovoid lesions (arrows’ head) were located deep in the periventricular fronto-parietal white matter with a long axis perpendicular to the ventricle, corresponding to the typical “Dawson fingers” pattern. c After nivolumab discontinuation, lesions enhancement progressively decreased in September 2018. d The lesions disappeared in December 2018, leading to the characteristic “black hole” pattern on T1-weighted images