A case of a 35-year-old woman with a 3 week history of headaches, short-term memory loss, and psychosis, diagnosed with anti-NMDA receptor encephalitis and ovarian tumor, is reported from the University of Rochester Medical Center, NY, and University of Pennsylvania Medical Center, Philadelphia. An EEG demonstrated nonconvulsive status epilepticus (NCSE). MRI showed hyperintensity in the right medial temporal lobe. Tests for viral and bacterial pathogens, including herpes simplex virus, were negative. CSF had an antibody for the NR1/NR2B heteromer of the NMDA receptor. Most AEDs were ineffective but propofol caused abrupt cessation of the rhythmic NCSE. Pentobarbital coma was required to maintain EEG-burst suppression and was continued for 5 months. IV immunoglobulin, cyclophosphamide, or rituximab were without effect. CTs and ultrasound of ovaries revealed only a cyst, but oopherectomy at 5 months uncovered an ovarian teratoma. Two weeks postoperatively she awakened, and within 4 weeks she was alert and conversant. At 5 weeks postoperativly, the EEG showed sleep-wake cycles and normal waking organization. Mild defects on naming and memory tests were present at 6 months follow-up, but no seizures had occurred. 
COMMENT. Anti-NMDA receptor encephalitis resistant to immonomodulatory therapies should be considered for oopherectomy, even when CT is not diagnostic of ovarian tumor.