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.