Clinical characteristics and treatment strategies of ovarian teratomas associated with anti-N-methyl-D-aspartate receptor encephalitis based on a case series

Introduction Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a potentially life-threatening yet reversible complication associated with ovarian teratoma. This study aims to systematically analyze the clinical features of anti-NMDAR encephalitis related to ovarian teratoma, with the goal of enhancing our understanding of the disease. Methods A retrospective analysis was performed on 17 patients with anti-NMDAR encephalitis associated with ovarian teratomas, who were admitted to Xuanwu Hospital, Capital Medical University, from August 2015 to August 2025. A systematic analysis was performed on their complete clinical data, including demographic characteristics, prodromal symptoms, typical neurological and psychiatric manifestations, cerebrospinal fluid and neuroimaging findings, anti-NMDAR antibody in cerebrospinal fluid, pathological features of the ovarian teratomas, comprehensive treatment strategies and follow-up outcomes. Results In this study, the age of the included patients was 25 years (21, 29). The time from symptom onset to diagnosis was 16 days (10.5, 27). The time from hospital admission to diagnosis was 4 days (2.5, 7). Two patients had a history of teratomas and methotrexate treatment. 15 patients (15/17, 88%) were directly admitted to the intensive care unit, while only 2 (2/17, 12%) were treated in general wards. The patients predominantly presented with multiple neurological abnormalities without clinical signs of teratoma compression. All patients received immunotherapy and tumor resection, and all patients achieved clinical improvement. At 3 months after surgery, mRS ≤ 2 was achieved in patients (4/17, 24%), mRS 3–4 in 5 paitents (5/17, 29%), and mRS 5 in 8 patients (8/17, 47%). Although all patients met the pre-defined criterion of clinical improvement in at least one neurological symptom, functional recovery remained limited. Conclusion A history of teratoma and methotrexate treatment may be associated with a higher risk of teratoma-associated anti-NMDAR encephalitis; however, this observation was based on only two patients and warrants further investigation. The disease is characterized by acute onset and rapid progression, and clinical improvement can be achieved through multidisciplinary collaboration combined with prompt immunotherapy and tumor resection.