Ovarian teratoma related anti-N-methyl-D-aspartate receptor encephalitis: A case series and review of the literature

BACKGROUND: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a rare but important complication of ovarian teratoma. Between July 2012 and December 2019, six patients with ovarian teratoma-associated anti-NMDAR encephalitis were enrolled in our hospital and their clinical characteristics, treatment, and follow-up were reviewed. We also conducted a systematic literature review of ovarian teratoma related anti-NMDAR encephalitis reports between January 2014 and December 2019. AIM: To better understand anti-NMDAR encephalitis through literature review and patients enrolled in our hospital. METHODS: The six patients enrolled in the study were those diagnosed with anti-NMDAR encephalitis. Their history, clinical manifestations, and medications were recorded and optimum treatment provided in addition to maintaining a record of the follow-ups. In addition, we also extensively surveyed the literature and provide summarized data from 155 published cases of anti-NMDAR encephalitis from 130 case reports. PubMed and Scopus were the sources of these publications and the time period covered was 6 years ranging from January 2014 through December 2019. RESULTS: The six patients enrolled for this study presented with typical symptoms resulting in a diagnosis of ovarian teratoma induced anti-NMDAR encephalitis. Appropriate interventions led to a positive outcome in all the patients, with five of six patients reporting full recovery and the sixth patient recovering with a few deficits. No death was recorded. The literature survey comprising of 155 patients cases across 130 case reports of anti-NMDAR encephalitis clearly indicated an upward trend in the reports/diagnosis in China, particularly in the surveyed time from 2014 through 2019. The majority of patients (150/155) underwent surgical intervention resulting in positive outcome. No treatment intervention was mentioned for one case while the four patients who were not surgically operated succumbed to the disease. CONCLUSION: Suspected anti-NMDAR encephalitis should be quickly evaluated for anti-NMDAR antibodies since early diagnosis is important. In case of a tumor, its earliest and complete removal is recommended. Finally, early use of corticosteroids and IgG-depleting strategies (intravenous immunoglobulin or plasma exchange) may improve outcome.