Anti-NMDAR Encephalitis Associated with an Ovarian Glioblastoma: A Case Report
Isaac Barsky-Ex1, Samuel Guzman2, Samuel Aragon2, Elizabeth Matthews2, Mallory Lowe2, Barrie Schmitt2, Douglas Ney3, Aaron Carlson4, Amanda Piquet5
1University of Colorado Anschutz Medical Campus, 2University of Colorado, Anschutz Medical Campus, 3University of Colorado School of Medicine, 4University of Colorado, School of Medicine, Department of Neurology, 5University of Colorado
Objective:
To describe a case report of anti-N-methyl-D-aspartate receptor encephalitis (NMDAR encephalitis) associated with a mature ovarian teratoma containing glioblastoma.
Background:
NMDARE can be seen associated with ovarian teratomas containing neural tissue, with ovarian teratomas present in approximately 30-60% of reproductive-age female patients. However, malignant transformation within these tumors is extremely rare. We present a case of anti-NMDARE associated with a mature ovarian teratoma containing WHO grade 4 glioblastoma.
Design/Methods:
Case Report
Results:
A 22-year-old woman with no previous medical history presented with acute anxiety, hallucinations, and a generalized tonic-clonic seizure. Cerebrospinal fluid (CSF) testing confirmed anti-NMDAR antibodies (1:512, Mayo Clinic Laboratories). Brain MRI was unremarkable, and pelvic imaging was interpreted as normal with a simple ovarian cyst. She received intravenous (IV) methylprednisolone, plasmapheresis, IVIg, and was enrolled in the ExTINGUISH clinical trial (Inebilizumab vs. Placebo, NCT04372615).
Her course was complicated by refractory seizures, dyskinesias, and paroxysmal sympathetic hyperactivity requiring tracheostomy and PEG placement despite immunotherapy. Repeat pelvic imaging was performed 5 weeks after presentation which showed a 3.3 cm thick-walled adnexal cystic lesion with a probable focus of fat. Surgical resection revealed a mature cystic teratoma with embedded hypercellular atypical neuroglial tissue. Histopathology showed frequent mitoses and diffuse GFAP positivity, while IDH1/2 and BRAF mutations were notably absent. Pathogenic mutations in TP53 (figure 1F) and ATRX were identified, consistent with WHO grade 4 glioblastoma arising within the teratoma.
Conclusions:
This case highlights a rare occurrence, a teratoma with somatic transformation to glioblastoma in NMDARE. Given that initial imaging may not be sensitive enough to detect small teratomas, if there is an absence of clinical improvement, a repeat and/or multi-modal imaging evaluation should be emphasized. Malignant glial tissue may contribute to autoimmune sensitization, similar to benign neural elements which have been described in other cases.
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