Polyarteritis nodosa with central nervous system involvement mimicking relapsing-remitting multiple sclerosis.

We report a patient with polyarteritis nodosa (PN) who showed frequent episodes of acute-onset central nervous system (CNS) involvement mimicking relapsing-remitting multiple sclerosis (MS) for 22 years. Long-term use of oral prednisolone successfully avoided recurrence of neurological symptoms. PN can sometimes affect the CNS, and is an important item in the differential diagnosis of neurological manifestations with lesion dissemination in time and space, as seen in MS.