Neuroimaging of Natalizumab Complications in Multiple Sclerosis: PML and Other Associated Entities

Figure 9

39-year-old woman with RRMS treated with natalizumab developed worsening symptoms. (a) MRI was performed at an outside institution demonstrating a new subcortical lesion in the right frontal lobe (arrow). She was treated for MS exacerbation. The patient presented to our institution approximately 3 months later with progressive symptoms and functional decline. (b) Repeat MRI shows increase in size of the right frontal lesion with characteristic bilateral, asymmetric distribution of lesions involving the subcortical U-fibers (arrows). (c) DWI shows a bright rim of signal along the advancing edge of the lesion (dashed arrows) with darker signal more anteriorly where the lesion is no longer active (dotted arrows). At this time there was no contrast enhancement (not shown). The patient was diagnosed with PML and PLEX was performed. Approximately one month later the patient experienced functional decline. Repeat MRI shows expansion of the (d) FLAIR lesions with increased swelling and mass effect and (e) the development of patchy central enhancement consistent with PML-IRIS. Note that the DWI image (f) no longer demonstrates an advancing edge of restricted diffusion.

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