Abstract Details

Title Shifting Mesial Temporal MRI Findings in a Rare Case of Anti-Glycine Receptor (GlyR) Autoimmune Encephalitis Mimicking Glioma

Topic Autoimmune Neurology

Presentation(s) P2 - Poster Session 2 (11:45 AM-12:45 PM)

Poster/Presentation
Number 1-012

Objective To describe a rare presentation of anti-glycine receptor (GlyR) antibody–associated autoimmune encephalitis manifesting as shifting mesial-temporal involvement on MRI, mimicking a neoplastic process.

Background Anti-GlyR antibodies are most commonly associated with progressive encephalomyelitis with rigidity and myoclonus (PERM) or Stiff Person Syndrome. Limbic encephalitis due to GlyR antibodies is rare, and radiologic findings are typically normal or show subtle T2/FLAIR abnormalities in the brainstem or spinal cord. Shifting or alternating laterality of mesial-temporal lesions is unusual and more commonly described in other autoimmune encephalitides such as anti-LGI1 or anti-GAD65.

Design/Methods We report a detailed clinical, radiologic, and laboratory evaluation of a 70-year-old woman presenting with progressive cognitive and behavioral decline over one year, initially thought to have a mesial temporal lobe glioma. Serial MRI scans, serum and CSF analyses, autoimmune antibody testing, and treatment response were reviewed.

Results

Initial MRI demonstrated a unilateral left mesial-temporal mass-like lesion with enhancement, leading to suspicion for a low-grade glioma. Over several months, follow-up MRI showed resolution of the left-sided abnormality and new right mesial-temporal enhancement, suggesting a dynamic autoimmune process rather than a static neoplasm. CSF studies were non-inflammatory, and initial autoimmune panels were negative. During hospitalization for encephalopathy, the patient developed rigidity and spasms consistent with Stiff Person features. Repeat serology identified anti-GlyR antibodies. Immunotherapy with benzodiazepines, corticosteroids, and limited IVIG led to transient improvement, though her course was complicated by infection, thrombosis, and eventual decline.

Conclusions This case highlights a rare presentation of anti-GlyR autoimmune encephalitis with shifting mesial-temporal involvement, initially mimicking a neoplastic process. Recognition of dynamic imaging changes and evolving clinical features is crucial in distinguishing autoimmune from structural etiologies. Early consideration of autoimmune encephalitis and prompt immunotherapy may improve outcomes in such atypical presentations.

Authors/Disclosures
Shaifali Arora, MD (Allegheny General Hospital) PRESENTER	Dr. Arora has nothing to disclose.
Priyanshu Bansal, MD	Dr. Bansal has nothing to disclose.
Andrea S. Synowiec, DO, FAAN (Allegheny Health Network)	Dr. Synowiec has received personal compensation in the range of $50,000-$99,999 for serving on a Speakers Bureau for Amgen. Dr. Synowiec has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Lilly. Dr. Synowiec has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Allergan. Dr. Synowiec has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Biohaven.

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