(A) Patient 2: cerebral MRI showing typical MS deep white matter lesions (A.a, T2w, axial plane) and partially confluent callosal lesions (A.b, FLAIR, sagittal plane). Furthermore, bilateral lesions in the periaqueductal gray (A.c, T2w, A.d: magnified view) and bilateral pontomedullary lesions were observed (A.e, T2w, A.f: magnified view). sMRI displaying LETM and segmental atrophy in the lower thoracic and lumbar spinal cord (A.g, level T8-T11). (B) Patient 1: sMRI showing multiple partially confluent lesions in the cervical cord from C1-C6 (FLAIR, sagittal) and in the thoracic cord with focal atrophy. (C) Patient 3: sMRI demonstrating LETM from C2-C5 (FLAIR, sagittal). FLAIR = fluid-attenuated inversion recovery; LETM = longitudinally extensive transverse myelitis; MS = multiple sclerosis; sMRI = spinal MRI; T2w = T2-weighted.