Abstract

Paraneoplastic Anti-NMDA Receptor Encephalitis Associated with Ovarian Teratoma: A Case Report

Author(s): Leonardo Antonio Ferrari1, André Nazário de Oliveira*1, Lethicia Domingos Paulo1, Cristhiany Ragnini Oliveira1, Iara da Costa Scharff1, Iane da Costa Scharff1, Raquel Marques Sandri1, Guilherme Eler de Almeida1, Gabriela Caroline de Paula Alcântara1, Carlos Henrique Spesia1, Jhonathan Gouveia1, Danilo Marcio de Oliveira Cardoso1, Mayara Teodoro Jacob Oliveira1, Jean Michel Loures do Couto1, Valeska Valiati1, Hozanna Holanda Brasil1, Daniele Tomazini Tirolli1, Lauhanda Alves de Lima1, Bruno Fuzari Silva1, Desirrê Leslíe Vizzotto dos Santos1, Fabiana Almeida Pereira1, Lucas Chiarato Fernandes1, Aline Lara Fonseca de Souza1, Barbara Bedim de Carvalho1, Luiza Putrick da Silva1, Caio Bortoleto Longhi1

Introduction: Anti-NMDA receptor antibody-mediated autoimmune encephalitis is a rare neurological condition often associated with ovarian Teratoma, particularly in young women. Early diagnosis is challenging due to its nonspecific clinical presentation. Case report: A 19-year-old female presented with flu-like symptoms, followed by seizures, behavioral changes, and lower limb weakness. Initial workup revealed an EEG with an “extreme delta brush” pattern and cerebrospinal fluid showing exocytosis without signs of infection. Abdominal CT identified a mass suggestive of an ovarian Teratoma, later confirmed by histopathology. Serology for anti-NMDA antibodies was positive. The patient underwent tumor resection and was treated with intravenous immunoglobulin, leading to significant clinical improvement and progressive neurological recovery. Discussion: Anti-NMDA receptor encephalitis should be considered in young women presenting with neurological and psychiatric symptoms, particularly when CSF and EEG findings are supportive. Early tumor resection and initiation of immunotherapy are associated with better outcomes. Normal neuroimaging does not exclude the diagnosis. Conclusion: Early diagnosis and timely therapeutic intervention are essential for neurological recovery in cases of autoimmune encephalitis associated with ovarian Teratoma. Ongoing follow-up is crucial for monitoring potential relapses. Keywords: Autoimmune Encephalitis, Anti-NMDA, Ovarian Teratoma, Immunotherapy, Neurology