[A case of an anti-Ma2 antibody-positive patient presenting with variable CNS symptoms mimicking multiple system...

A 70-year-old man with a 5-month history of progressive bradykinesia of the bilateral lower extremities was admitted to our hospital. At the age of 64, he underwent proximal gastrectomy for gastric cancer. He also had a history of subacute combined degeneration of the spinal cord since the age of 67, which was successfully treated with vitamin B12 therapy. Four weeks before admission to our hospital, he admitted himself to his former hospital complaining of walking difficulty. Two weeks later, however, his symptoms progressed rapidly; he was immobilized for two weeks and did not respond to the vitamin therapy. On admission to our hospital, he showed moderate paralysis of the lower extremities, cog-wheel rigidity of the four extremities, and dystonic posture of his left hand. He also showed orthostatic hypotension and vesicorectal disorders. Blood examination and cerebrospinal fluid analysis revealed no remarkable abnormalities. Electroencephalography showed frontal dominant, high voltage, sharp waves. His brain and spinal MRI revealed no notable abnormalities. We suspected autoimmune disease and commenced one course of intravenous methylprednisolone therapy, resulting in improvement of the parkinsonism and orthostatic hypotension. Based on these results, we investigated possible neural antigens and detected anti-Ma2 antibody. In addition to limbic encephalitis, anti-Ma2 antibody-positive neural disorders are characterized by rapid eye movement sleep behavior disorders or parkinsonism. Here, we report an anti-Ma2 antibody positive patient presenting variable CNS symptoms mimicking multiple system atrophy, who responded to immunotherapy.