Advanced imaging findings in progressive solitary sclerosis: a single lesion or a global disease?

BACKGROUND: Progressive solitary sclerosis is a unifocal demyelinating disease recently proposed as a possible multiple sclerosis variant. OBJECTIVE: To compare myelin content and brain metabolite ratio qualitatively in the normal-appearing white matter of progressive solitary sclerosis cases compared to multiple sclerosis and healthy control participants. METHODS: Case report. RESULTS: Progressive solitary sclerosis cases showed abnormal myelin in normal-appearing white matter tracts and global normal-appearing white matter as well as lower N-acetyl-aspartate to total creatine ratio compared to multiple sclerosis and healthy control groups. CONCLUSION: Despite a single demyelinating lesion along the corticospinal tract in progressive solitary sclerosis, we showed evidence of more extensive abnormality within the normal-appearing white matter.