Study Objective: To describe the incidence of ovarian dermoid cysts associated with paraneoplastic encephalitis syndrome due to N-methyl-D-aspartic acid (NMDA) receptor antibodies among women undergoing surgical resection of dermoid cysts. Design: Retrospective cohort study. Setting: University-affiliated department of obstetrics and gynecology. Patients: All patients with pathology-proven ovarian dermoid cysts who underwent surgical resection in our department between January 2008 and December 2019. Their demographic, clinical, and surgical characteristics are described, with emphasis on cases diagnosed with anti-NMDA receptor encephalitis. Interventions: Ovarian dermoid cyst resection by cystectomy or salpingo-oophorectomy. Measurements and Main Results: A total of 233 patients were operated on for ovarian dermoid cysts, comprising 2 cases diagnosed with anti-NMDA receptor encephalitis (0.85%). Among the women without NMDA receptor encephalitis, the mean age was 33.3 ± 14.9 years, 84.0% were of reproductive age, 5.2% were premenarchal, and 10.8% were menopausal. The mean diameter of the dermoid cyst in this group was 77.3 ± 33.3-mm. The 2 patients diagnosed with anti-NMDA receptor encephalitis were 21 years old and 42 years old. The diameters of their dermoid cysts were 15-mm and 80-mm, respectively. The patients with anti-NMDA receptor encephalitis were managed with laparoscopic resection, plasmapheresis, intravenous immunoglobulins, and corticosteroids; 1 patient also received immunosuppressive treatment. Both recovered without significant neurologic sequela. Conclusion: Paraneoplastic syndrome due to NMDA receptor antibodies is a rare complication of dermoid cysts. This complication may occur in younger or older women, as well as in small- or large-diameter cysts. Thus, a high index of suspicion is required to correctly diagnose and treat women presenting with neurologic symptoms in the presence of dermoid cysts.
- Anti-NMDA receptor encephalitis
- Benign cystic teratoma
- Ovarian dermoid cyst