Multiple system atrophy mimics CASPR2 antibody-associated disease: a case report.

Aim: Multiple system atrophy (MSA) and CASPR2 antibody-associated disease bear their own characteristics.Case presentation: A 58-year-old woman presented with a 26 months history of uncoordinated gait and slurred speech. Her serum was positive for anti-CASPR2 antibodies, and MRI revealed atrophy of the brainstem and cerebellum. She underwent three plasma exchanges (PE) and received high doses of corticosteroids without any apparent effect. Her autonomic dysfunction improved after repetitive transcranial magnetic stimulation. Eventually, a diagnosis of MSA-cerebellar phenotype(MSA-C) was made.Conclusion: With increased availability of tools for neuron antibody detection, physicians need to be aware of the possibility that antibodies may accompany other diseases. This report underscores the modern dilemmas caused by available and extensive neuron antibody testing.