Four-year-old anti-N-methyl-D-aspartate receptor encephalitis patient with ovarian teratoma: A case report.

Background: A population-based comparative study in United States shows that the prevalence and incidence of autoimmune encephalitis are comparable to those of infectious encephalitis and its detection is increasing over time. Some patients are complicated with ovarian teratoma. The younger the patient is, the less likely a tumor will be present.