Multiple system atrophy with anti-NAE antibody refractory to immunotherapy: A case report.

A 51-year-old Japanese man presented with slowly progressing cerebellar ataxia from age 49. Anti-thyroglobulin, anti-thyroid peroxidase, and anti-NAE antibodies were detected. Brain magnetic resonance imaging showed moderate atrophy of the pons, cerebellum, and middle cerebellar peduncle. Dopamine transporter single-photon emission computed tomography showed normal uptake. With the diagnosis of Hashimoto's encephalopathy, repeated steroid pulse therapy and intravenous immunoglobulin therapy were administered; however, they were ineffective for cerebellar ataxia. Afterwards, autonomic failure and parkinsonism became evident. The final diagnosis was MSA of the cerebellar type. Immunotherapies for patients with MSA with anti-NAE antibodies should be carefully considered.