PMC4258922_01
Axial T2-weighted (top row) and contrast-enhanced T1-weighted images (bottom row) obtained during Natalizumab treatment (3 December 2012), at the time of Natalizumab discontinuation (22 April 2013), at the time of PML-IRIS occurrence (16 September 2013), and after PML-IRIS treatment (21 October 2013). A small lesion suggestive of PML was already visible at the time of Natalizumab discontinuation (arrow). During Fingolimod treatment, this lesion progressed and changed to a PML-IRIS manifestation with slight mass effect and contrast enhancement (arrows) leading to posttreatment sequelae (arrow).
CRINM2014-307872.001.jpg
PMC4258922_01_CRINM2014-307872.001.jpg
fig1
At that time (22-04-2013), brain MRI showed a new, small lesion in the cortical grey matter of the right precentral gyrus, which, according to recently published PML imaging characteristics, can be interpreted retrospectively as PML onset (see Figure 1). On 16 September 2013, brain MRI showed evolution and an enhancement pattern suggestive of PML-IRIS (Figure 1).