Complete recovery from paraneoplastic anti-NMDAR encephalitis associated with a small ovarian teratoma following a laparoscopic salpingo-oophorectomy: A case report

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a severe but treatment-responsive disorder, initially identified in young women with an ovarian teratoma. Symptoms include mood, behavior and personality irregularities that resemble acute psychosis. The present study reports the rare case of a patient with anti-NMDAR encephalitis and severe neurological symptoms, that exhibited a rapid recovery following a laparoscopic salpingo-oophorectomy. The 39-year-old woman was admitted to the Department of Obstetrics and Gynecology, Osaka City University Graduate School of Medicine (Osaka, Japan) with a 5-day history of fever and stomach ache. One week later, the patient developed hallucinations and emotional lability. Initially, a diagnosis of limbic or herpes encephalitis was considered; thus, the patient was administered acyclovir and received steroid pulse therapy. However, the patient subsequently developed apnea, and in response, a tracheal intubation, mechanical ventilation and plasmapheresis were performed. Anti-NMDAR encephalitis was subsequently considered as a diagnosis and mediastinal and pelvic computed tomography (CT) examinations were conducted to detect for the presence of a teratoma. A 24x24-mm cystic lesion was identified in the pelvis from an abdominal CT scan and the lesion appeared to be an ovarian teratoma. In addition, serum and cerebrospinal fluid samples were collected, and were found to test positive for anti-NMDAR antibodies. A laparoscopic salpingo-oophorectomy was performed, which resulted in rapid improvement of the patient's mental symptoms, followed by a complete recovery.