Here we report the clinical,radiological and neuropathological findings of a patient with tumor-like inflammatory demyelinating diseases of the central nervous system.The patient was a 51-year-old man with a four-month history of inflammatory pseudotumor and no other significant medical history,who presented to our hospital recurrent relapse numbness and weakness of his right extremities,dysarthria and memory deterioration.Brain magnetic resonance imaging(MRI) showed mass focal lesion in white matter of left parietal lobes.The biopsy showed numerous infiltrating macrophages and lymphocytes within the perivascular.The patient responded clinically to corticosteroid and intravenous immunoglobulin(IVIG) therapy.According to the results of the biopsy and the MRI,a diagnosis of inflammatory pseu-dotumor of the central nervous system was made.The vascular dysfunction may act in the pathogenesis of inflammatory pseudotumor of the central nervous system.