Figure 1a and 1b. Magnetic resonance examinations of Patient 1. MR examinations were performed on a 1.5 T Magnetom Vision Plus system (Siemens, Erlangen, Germany). The imaging protocol included one axial and coronal T2-weighted sequence and one axial T1-weighted sequence, performed before and after contrast agent administration not at diagnosis but before treatment, after 18 months of treatment, at relapse, and after 17 months of a new treatment. A multimodal MRI of Patient 1 at the time of the diagnosis disclosed multiple brain lesions located in the medulla oblongata, the hypothalamus, the internal side of the right temporal lobe, the bilateral fornix, the lenticular nuclei and the head of caudate nuclei. These nonspecific, but unusual, lesions have a high signal intensity on FLAIR images and low signal intensity on MT images. They are slightly enhanced on T1-weighted images after gadolinium administration. Complete normalisation of the FLAIR abnormalities after 18 months of treatment were observed. A new lesion appeared in the left medulla oblongata during the relapse; it was enhanced after gadolinium injection. FLAIR abnormalities reappeared during the relapse, and lenticulocaudate gadolinium enhancement was also observed. A complete disappearance of the lesions after 17 months of treatment and the complete disappearance of gadolinium enhancement were also observed, in accordance with clinical improvement.