Anti-N-Methyl-D-Aspartate Receptor Encephalitis Associated with Mature Ovarian Teratoma in a Young Adolescent: A Case Report.

BACKGROUND: Ovarian teratoma has an uncommon association with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis. This is a life-threatening condition, and here, we describe a case of an adolescent girl with anti-NMDAR encephalitis caused by an ovarian teratoma.

CASE: A 14-year-old girl presented with acute features of fever, severe headache, altered behavioral changes, delirium, autonomic instability, episodes of seizure, and involuntary movement over a period of 1 month. Upon investigation, electroencephalogram (EEG), computed tomography (CT), and magnetic resonance imaging (MRI) of her brain showed normal findings. Her serum and cerebrospinal fluid were positive for anti-NMDARs, and a diagnosis of anti-NMDAR encephalitis was made, so she received a course of intravenous methyl prednisolone and immunoglobulin and was discharged after her neurological status improved. Upon further workup, she was suspected to have a left ovarian dermoid cyst on transabdominal ultrasonogram, which was an incidental finding. Her tumor marker panel showed normal serum lactate dehydrogenase, beta human chorionic gonadotropin, inhibin, alpha-fetoprotein, and carcinoembryonic antigen and a cancer antigen 125 level of 71.5 U/L. She eventually underwent laparoscopic left ovarian cystectomy and received immunotherapy in the postoperative period. She was discharged in stable condition on postoperative day 4. On histopathological examination, the specimen revealed a mature cystic teratoma with glial component. One year after surgery, the patient has recovered completely and has no residual psychiatric or neurological symptoms.

CONCLUSION: Complete recovery after surgery in cases of anti-NMDAR encephalitis with ovarian teratoma emphasizes the need for early recognition of the entity, search for underlying tumor, and tumor removal to improve the prognosis.