title: Extralimbic autoimmune encephalitis associated with glutamic acid decarboxylase antibodies: an underdiagnosed entity?
abstract: Nonparaneoplastic glutamic acid decarboxylase antibody (GADAb)-related autoimmune encephalitis is a syndrome characterized by refractory seizures, progressive cognitive deficits, and psychiatric manifestations. The limbic subtype is well described, has characteristic affective and memory disturbances, and typical mesial temporal MRI abnormalities. We found only one single case report of the extralimbic subtype. We report clinical, radiological, and pathological findings of two additional cases with contrast-enhancing lesions. One of our cases presented as vasculitis, and the other imitated a tumor. Pathological evidence of both vasculitis and encephalitis has never been previously reported in any inflammatory condition affecting the brain. Our cases confirm prior reports that immune therapy can better control seizures associated with GADAb autoimmune encephalitis, and support the rationale for assaying for GADAb titers in patients with etiologically unclear extralimbic lesions and refractory epilepsy, independent of seizure types.
authors.affiliation: NYU Comprehensive Epilepsy Center, New York University School of Medicine, New York, NY 10016, USA. mna1024231@aol.com
authors.forename: Souhel
authors.initials: S
authors.lastname: Najjar
authors.forename: Daniel
authors.initials: D
authors.lastname: Pearlman
authors.forename: Amanda
authors.initials: A
authors.lastname: Najjar
authors.forename: Vahid
authors.initials: V
authors.lastname: Ghiasian
authors.forename: David
authors.initials: D
authors.lastname: Zagzag
authors.forename: Orrin
authors.initials: O
authors.lastname: Devinsky
mesh_terms: D000328:Adult; D000368:Aged; D000906:Antibodies / Q000097:blood*; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D001921:Brain / Q000473:pathology; D001927:Brain Diseases / Q000097:blood* / Q000175:diagnosis; D004660:Encephalitis; D005260:Female; D005682:Gadolinium; D005968:Glutamate Decarboxylase / Q000276:immunology*; D050031:Hashimoto Disease / Q000097:blood* / Q000175:diagnosis; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D000097382:CD68 Molecule
chemical_list: D000906:Antibodies; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D005682:Gadolinium; D005968:Glutamate Decarboxylase; C067980:CD68 antigen, human; D000097382:CD68 Molecule