Clinical deterioration due to co-occurrence of multiple sclerosis and glioblastoma: report of two cases.

Clinical worsening during the course of multiple sclerosis (MS) might be secondary to not only an incomplete recovery after relapses, to progressive accumulation of deficits, but also to other etiologies, different from MS. This report discusses the cases of two MS patients showing a gradual and progressive deterioration of locomotor and cognitive functions which were due to the co-occurrence of MS and glioblastoma. Additional investigations (especially magnetic resonance imaging) are strongly recommended to exclude concomitant pathologies in MS patients suffering from new neurological symptoms over weeks to months, without remission, or an unexpected rapid and progressive accumulation of disability.