[Successful treatment with rituximab in unilateral relapsing primary CNS vasculitis: a case report].

We report a case of unilateral relapsing primary CNS vasculitis (PCNSV) treated with Rituximab. A 52-year old man initially diagnosed as PCNSV by brain biopsy. He was treated with corticosteroids and no recurrence had been recognized for 4 years. However, after the reduction of corticosteroids to 9 mg, PCNSV recurred many times only in the right hemisphere. Mycophenolate mofetil and cyclophosphamide were not effective. We diagnosed this patient as unilateral relapsing PCNSV (UR-PCNSV), which is resistant to treatment and repeatedly relapses unilaterally. After rituximab was introduced, there was no clinical recurrence and abnormal lesions on head MRI improved. We emphasize that rituximab is a good candidate drug for treating the UR-PCNSV.