December 2025

NEUROSCIENCES

CASE REPORT: RAPIDLY PROGRESSIVE MEMORY CHANGES IN A 66-YEAR-OLD PATIENT

Clinical presentation
An otherwise healthy 66-year-old woman presented to Northwestern Medicine Neurology with 3 months of worsening short-term memory loss, executive dysfunction and emotional lability.

Initial evaluation
Preliminary MRI revealed symmetric FLAIR hyperintensities in the thalami, paramedian frontal regions, and mesial temporal lobes without contrast enhancement, an atypical pattern that initially suggested autoimmune encephalitis.
  • CSF was non-inflammatory
  • RT-QuIC and autoimmune panels were negative
  • PET-CT was unrevealing
  • EEG showed intermittent slowing without epileptiform discharges

​Treatment and disease progression
The patient was treated empirically for seronegative autoimmune encephalitis with corticosteroids and plasma exchange, with mild initial improvement. One month later, she developed status epilepticus and obstructive hydrocephalus requiring external ventricular drain placement. A second course of immunotherapy was ineffective.

Definitive diagnosis
MR spectroscopy suggested malignancy, and biopsy confirmed glioblastoma, IDH-wildtype, WHO grade 4, MGMT-unmethylated, with TERT and EGFR mutations.
The infiltrative, non-enhancing presentation mimicked inflammatory disease, underscoring the diagnostic challenge.

Key takeaways
  • Rapidly progressive dementia with deep gray matter involvement warrants a broad differential and early biopsy.
  • Glioblastoma can present without classic enhancement or necrosis, particularly in thalamic or infiltrative patterns.
  • Hydrocephalus and refractory seizures should raise suspicion for neoplasm.
  • Prognosis is poor for thalamic GBMs, especially IDH-wildtype and MGMT-unmethylated profiles.
Karan Dixit, MD, Assistant Professor of Neurology at Northwestern Medicine
Dan Tong Jia, MD, Assistant Professor of Neurology at Northwestern Medicine
Daniel Brat, MD, PhD, Chair of the Department of Pathology, Magerstadt Professor of Pathology, and Professor of Pathology (Experimental Pathology and Neuropathology) at Northwestern Medicine 

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