Familial Mediterranean fever and multiple sclerosis.

Central nervous system (CNS) manifestations of familial Mediterranean fever (FMF) are extremely rare. These include pseudotumor cerebri, optic neuritis, CNS complications of polyarteritis nodosa type vasculitis, or hypercoagulable states secondary to renal amyloidosis, recurrent aseptic meningitis, and amyloid ophthalmoplegia. We present three patients with FMF whose neurological findings and magnetic resonance imaging (MRI) abnormalities resembled multiple sclerosis (MS). These two conditions in the same patient could arise from either coincidence or an unknown pathophysiological relationship. Both explanations are equally speculative and this matter needs further study, especially to investigate MRI features in FMF patients without CNS symptoms.