SHM Converge Scientific Abstract ePoster Gallery-A Mind of Its Own: Malignant Transformation of an Ovarian Teratoma to Glioblastoma Presenting as Nmdar Encephalitis

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A 22-year-old woman with no prior medical history presented to the emergency department with insomnia, anxiety, and hallucinations. She was initially treated with antipsychotics and admitted to behavioral health, but her symptoms worsened and she returned with severe agitation that did not respond to antipsychotic therapy.<br /><br />Further workup showed inflammatory cerebrospinal fluid findings and strongly positive NMDA receptor IgG titers in both CSF and serum, consistent with NMDA receptor encephalitis. Imaging later revealed an ovarian cystic lesion, better seen on transvaginal ultrasound, ultimately identified as a mature cystic teratoma with malignant transformation to glioblastoma.<br /><br />This case is notable for several reasons. Mature cystic teratomas are common ovarian germ cell tumors, but malignant transformation is rare, occurring in only about 1.5–2% of cases. Squamous cell carcinoma is the most frequent malignant change, while transformation to neuroectodermal tumors such as glioblastoma is exceptionally uncommon. The presentation also underscores the strong association between ovarian teratomas and NMDA receptor encephalitis.<br /><br />The patient improved with immunosuppressive therapy, and her clinical course showed gradual neurologic recovery. She was later decannulated, had her PEG removed, regained the ability to follow complex commands and speak in complete sentences, and could ambulate again. The case highlights the need to consider ovarian teratoma in patients with NMDA receptor encephalitis and demonstrates that symptom improvement may occur with immunosuppression, while definitive management required surgical resection of the underlying tumor.

Asset Subtitle

Alison J. White

Meta Tag

Author List Alison J. White, Amanda M. Miller-Sarmento, Jason John, Lauren Dailey, Rudolph Moravek, Steffi Hu

Category Clinical Vignettes

Concept Anti-NMDA Receptor Encephalitis

Concept Autoimmune Encephalitis

Concept Ovarian Teratoma

Concept Inflammatory Encephalitis

Concept Immunosuppressive Therapy

Distinguished Non-Finalist

Presenter Organization University of Colorado

Presenting Author Alison J. White

Track Adult

Keywords

NMDA receptor encephalitis

ovarian teratoma

mature cystic teratoma

glioblastoma

malignant transformation

hallucinations

severe agitation

cerebrospinal fluid inflammation

immunosuppressive therapy

transvaginal ultrasound

Anti-NMDA Receptor Encephalitis

Autoimmune Encephalitis

Ovarian Teratoma

Inflammatory Encephalitis

Immunosuppressive Therapy