Acute Disseminated Encephalomyelitis in FET PET/MR

Area of Science:

• Neurology
• Neuroimaging
• Pathology

Background:

• A 28-year-old woman presented with a first-time generalized seizure after 3 weeks of daily headaches.
• Initial CT revealed a left frontal mass with perifocal edema, raising suspicion for cerebral lymphoma.

Purpose of the Study:

• To differentiate between cerebral lymphoma and other potential causes of a brain mass presenting with seizure.
• To investigate the diagnostic utility of advanced imaging techniques in this clinical scenario.

Main Methods:

• Computed Tomography (CT) scan of the brain.
• Magnetic Resonance Imaging (MRI) of the brain.
• Cerebrospinal fluid (CSF) analysis.
• Fluorine-18-fluorodeoxythymidine (FET) Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI).
• Brain biopsy for histopathological examination.

Main Results:

• CSF analysis showed mononuclear pleocytosis but no malignant cells, with normal protein and no oligoclonal bands.
• FET PET/MRI demonstrated characteristics consistent with inflammatory disease, not neoplastic processes.
• Histopathological examination of the brain biopsy definitively confirmed acute disseminated encephalomyelitis.

Conclusions:

• Acute disseminated encephalomyelitis can present as a focal brain mass mimicking primary brain tumors like lymphoma.
• Multimodal diagnostic approaches, including advanced neuroimaging (FET PET/MRI) and histopathology, are crucial for accurate diagnosis.
• Early and accurate diagnosis is essential for appropriate management of inflammatory demyelinating diseases.