Objective:

To describe three cases of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis associated with immature ovarian teratomas.

Background:

Anti-NMDAR encephalitis is an autoimmune paraneoplastic neurological condition associated with ovarian teratoma in approximately 50% of adult cases. In most cases, the teratoma is mature with no immature components, but immature teratomas have been reported in 11-15% of larger studies. There remains a lack of consensus regarding management of immature teratomas.

Design/Methods:

Three cases of patients with definite anti-NMDAR encephalitis with immature ovarian teratomas are included in this series.

Results:

Case 1 is a 35-year-old woman with anti-NMDAR encephalitis found to have a mass favored to be a mature ovarian teratoma on MRI. She underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy. Pathology showed a stage 1C immature teratoma. She underwent surveillance CT every six months for two years, then annually for five years, which did not show tumor recurrence. Case 2 is a 17-year-old girl with abdominal pain and a palpable pelvic mass, found to have bilateral ovarian teratomas. She presented eight years later with anti-NMDAR encephalitis with a mass seen on MRI favored to be a mature ovarian teratoma. Bilateral salpingo-oophorectomy was undertaken with pathology showing a stage 1A immature teratoma. Surveillance imaging with follow-up 43 months later did not show tumor recurrence. Case 3 is a 25-year-old woman with anti-NMDAR encephalitis with pelvic ultrasound showing a heterogeneous cystic and solid mass with hyperechoic foci. Pathology from resection of the mass showed a stage 1C immature ovarian teratoma. She received adjuvant chemotherapy (bleomycin, etoposide, cisplatin) for three cycles. She remains cancer free after 3.5 years.

Conclusions:

Anti-NMDAR encephalitis associated with immature ovarian teratoma should be managed collaboratively between Neurology and Gynecology. After tumor resection, these patients should undergo surveillance imaging, and depending on the stage of the tumor, may warrant adjuvant chemotherapy.