Longitudinally Extensive Myelitis Associated With Immune Checkpoint Inhibitors

(A) Spinal MRI at diagnosis in patient 3, showing multiple hyperintensities at C4-C5, T9-T11, and T12 on sagittal T2/STIR sequences, with focal areas of contrast enhancement on T1 sequences after gadolinium injection (circles). (B) Spinal and brain MRI at diagnosis in patient 4, who had positive antibodies to glial fibrillary acidic protein. Spinal MRI showed a faint hyperintensity at T10-T12 on T2/STIR sequences and a marked contrast enhancement of the anterior portion of the dural sac and of filum terminale on T1 sequences after gadolinium injection. Brain MRI in the same patient showed linear rims of contrast enhancement expanding radially from lateral ventricles. (C) Brain MRI at diagnosis in patient 7 showing small punctuate areas of contrast enhancement in bilateral subcortical and deep white matter, without corresponding signal alterations on FLAIR sequences (not shown). (D) Control spinal MRI of the thoracic tract (sagittal T2/STIR sequences) in patient 1, 15 days after starting treatment with high-dose glucocorticoids and plasmapheresis, showing an almost complete resolution of the longitudinally extensive hyperintensity of the spinal cord compared with initial imaging. (E) Control spinal MRI of the lumbar tract (sagittal T2/STIR and T1 sequences after gadolinium injection) in patient 7, 15 days after starting treatment with high-dose glucocorticoids, plasmapheresis, tocilizumab, and ruxolitinib, showing a marked reduction of the hyperintensity and swelling of the conus and of the associated leptomeningeal and caudal root enhancement compared with initial imaging. ICI = immune checkpoint inhibitor.