Progressive multifocal leukoencephalopathy in a patient with relapsing multiple sclerosis treated with ocrelizumab: A case report.

INTRODUCTION: Progressive multifocal leukoencephalopathy is a rare but often fatal complication of some multiple sclerosis treatments. Although it has mainly been associated with natalizumab treatment, its appearance with other immunosuppressive therapies has also been reported. AIMS: The aim of this case report is to describe the development of progressive multifocal encephalopathy in a patient with relapsing-remitting multiple sclerosis treated with ocrelizumab without previous use of natalizumab. CONCLUSIONS: A summary of the presentation and disease course is provided, presented in the context of the current literature and likely pathophysiology.