Multiple co-existing antibodies in autoimmune encephalitis: A case and review of the literature.

A 66-year-old man with a history of chronic tobacco use presented with two months of progressive memory deficits, ataxia, diplopia, and opsoclonus. His brain magnetic resonance imaging (MRI) showed limbic and brainstem encephalitis, and antibody testing was positive for anti-Ma1/Ma2, anti-N-methyl-d-aspartate receptor (anti-NMDA-R) and anti-glutamic acid decarboxylase 65 (anti-GAD65) antibodies. His encephalitis improved with intravenous steroids, plasmapheresis, and rituximab initiation. His PET/CT was suspicious for lung malignancy, but a progressive deterioration of his respiratory status prevented full investigation. Multiple auto-antibodies may be produced in response to a malignancy and overlapping of clinical presentations may occur with multiple auto-antibodies.