A Twice-Vanishing Lesion: Recurrent Stroke Mimic Reveals Cerebral Amyloid Angiopathy-Related Inflammation

Cerebral amyloid angiopathy-related inflammation (CAA-RI) is an uncommon inflammatory complication of CAA that can mimic stroke. Early recognition is critical, as the condition is often responsive to immunosuppressive therapy. We report a case of CAA-RI in a 63-year-old woman who presented twice with stroke-like symptoms, recurring seven years after the initial episode. Diagnosis is made on the basis of clinical suspicion and characteristic brain findings, which can be reversed with or without steroids. She first presented with confusion and vertigo. Magnetic resonance imaging (MRI) of the head with contrast showed increased T2 and fluid-attenuated inversion recovery (FLAIR) signal, along with hyperintensity on diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) in the right temporal lobe. She was started on dexamethasone 8 mg twice daily for a suspected tumor. On further review of the scans in the neuroradiology multidisciplinary team (MDT) meeting, the pattern of enhancement was not typical of a tumor, and the presence of punctate areas of hemosiderin deposition in both cerebral hemispheres on gradient-echo T2-weighted axial images was more suggestive of cerebral amyloid angiopathy/vasculopathy. Two months later, there was complete clinical and radiological resolution. After seven years, she presented with bilateral arm numbness and aphasia lasting for one hour. MRI showed features of a subacute infarct in the left middle cerebral artery territory, and the patient was treated with high-dose aspirin in view of the stroke. MRI performed for further characterization demonstrated subcortical T2 hyperintensity in the left temporoparietal region, with no underlying mass effect and no enhancement on post-gadolinium T1-weighted or FLAIR images. These findings were suggestive of cortical epileptic changes. The presence of subarachnoid FLAIR high signal was also noted, raising the possibility of meningitis or cerebritis. This was ruled out with a lumbar puncture (LP). Following a multidisciplinary team (MDT) discussion, she was diagnosed with cerebral amyloid-related seizure disorder. Repeat MRI at two months showed significant resolution of radiological changes, and MRI of the head after one year demonstrated complete radiological resolution. The diagnostic challenge faced by the treating physician, due to the clinical dilemma arising from varied presentations, can often lead to delayed or missed diagnosis. However, prompt recognition and treatment may result in full clinical and radiological recovery.