(63) Laparoscopic Ultrasound Probe-Assisted Ovarian Sparing Cystectomy in a Patient with Anti-NMDAR Encephalitis: A Case Report

Background: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a rare and often difficult to diagnose disease primarily affecting young women leading to escalating neuropsychiatric features. Around half of cases are associated with teratomas with therapy focusing on early surgical resection and immunotherapy. One challenge is balancing complete resection of a very small dermoid while minimizing resection of surrounding ovarian cortex. We describe a unique approach for complete resection of a very small teratoma using a laparoscopic ultrasound probe for live intra-operative guidance to ensure ovarian sparing.

Case: We present a case of a 15 year-old previously healthy female brought into care after one week of headache, irritability, and erratic, disinhibited behavior changes along with an altered mental state. Her toxicology screen, HSV PCR, and meningitis workup were negative. Her initial brain MRI showed leptomeningeal enhancement in bilateral cerebral sulci. She was evaluated by Neurology and Neuroimmunology with concern for autoimmune encephalitis and started on IV steroids. Initial serum NMDAR Ab IgG S was negative ( < 1:10) with diagnosis later confirmed with serum NMDAR AB 1:20. She underwent a pelvic ultrasound that revealed a 1.4 x 1.2 x 1.3 cm hyperechoic lesion in her left ovary. Tumor markers including serum hCG, Ca 125, AFP, and LDH were within normal limits. Given her deteriorating neurologic function and desire to maximize all potential treatment options she underwent a laparoscopic cystectomy using an intra-operative laparoscopic ultrasound probe (Fujifilm; probe C9150LA) for cyst identification and complete resection with ovarian sparing technique. No postoperative complications were encountered. During the procedure, a TVUS was initially performed by a skilled sonographer to locate the ovarian pole of the dermoid. After insufflation, due to imaging limitations, a laparoscopic ultrasound probe was used. Pathology confirmed the diagnosis of a 2 x 1.5 x 1.3 cm mature teratoma. Patient experienced progressive return of neurological function, completed inpatient rehabilitation, continued immunotherapy and was discharged home with outpatient multi-disciplinary care by postoperative week 3. She continues with outpatient follow-up.

Comments: Anti-NMDAR encephalitis is a debilitating disease associated with teratomas. Ovarian sparing surgery should be regarded as first line treatment in all patients, particularly those with fertility potential. Use of the laparoscopic ultrasound probe can aid with intra-operative delineation of adnexal masses, particularly those that are deep and very small where complete resection is central to achieving therapeutic goal.