Two Cases of Encephalitis without Anti-N-methyl-D-aspartate Receptor Antibody Successfully Treated with Ovarian Teratoma Resection and Immunotherapy

Intern Med. 2022 Nov 2. doi: 10.2169/internalmedicine.0447-22. Online ahead of print.

Abstract

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune disorder sometimes accompanied by ovarian teratoma. However, the concept of encephalitis without anti-NMDAR antibodies successfully treated with ovarian teratoma resection and immunotherapy has not been established. We herein report two such cases. Case 1 exhibited delayed magnetic resonance imaging abnormalities in the thalamus and basal ganglia, despite clinical improvement. Case 2 presented with brainstem encephalitis similar to Bickerstaff's encephalitis. Although both patients tested negative for anti-NMDAR antibodies, the recovery of the neurological function and good prognosis following tumor resection with immunotherapy indicated a close association between these diseases and ovarian teratoma.

Keywords: Bickerstaff's encephalitis; anti-NMDAR encephalitis; ovarian teratoma; seronegative.