A case of anti-N-methyl-D-aspartate receptor antibody encephalitis associated with immature ovarian teratoma

Abstract

Introduction: Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is typically associated with mature cystic teratomas. We report a case of anti-NMDA receptor encephalitis associated with an immature ovarian teratoma, which is a malignant tumor. Case: A 16-year-old girl who presented with impaired consciousness and abnormal behavior was referred to our hospital. After evaluation upon admission, she was diagnosed with anti-NMDA receptor encephalitis associated with an ovarian mature cystic teratoma, and laparoscopic right salpingo-oophorectomy was performed. The postoperative pathological diagnosis confirmed the presence of an immature ovarian teratoma. The patient subsequently underwent immunoglobulin therapy, steroid pulse therapy, and plasma exchange for the treatment of encephalitis. Bleomycin, etoposide, and cisplatin chemotherapy was administered after her symptoms improved. Conclusions: In this case, early collaboration among the departments of neurology, obstetrics and gynecology, and emergency medicine enabled a prompt diagnosis and effective treatment. The patient’s symptoms were successfully ameliorated through early removal of the tumor and pharmacotherapy. Although anti-NMDA receptor encephalitis generally has a favorable prognosis, early diagnosis and initiation of treatment considerably affect the outcome. Clinicians should suspect anti-NMDA receptor encephalitis when a young patient presents with impaired consciousness or abnormal behavior and consider the possibility of underlying malignant tumors.