FLAIR-hyperintense lesions in anti-MOG associated encephalitis with seizures (FLAMES)

Last revised by Daniel J Bell on 7 Jun 2023

FLAIR-hyperintense lesions in anti-MOG associated encephalitis with seizures (FLAMES) is a clinicoradiographic sub-entity of MOGAD comprising seizures and FLAIR-hyperintensities on MRI, particularly involving the cerebral cortex 1,2.

Epidemiology and treatment are covered in a general discussion of myelin oligodendrocyte glycoprotein​ antibody-associated disease (MOGAD).

As the name suggests, the clinical presentation includes:

  • seizure with additional symptoms including 3:

    • headache

    • fever

    • specific neurological deficits referable to the cortical lesions

CSF samples reveal a pleocytosis and elevated proteins with normal glucose ratios are described 3.

FLAMES is characterized by high T2 signal cortical lesions that are usually unilateral although bilateral involvement has been described 2,3. These lesions can have high signal on DWI 3

Additionally, leptomeningeal abnormalities can be seen with sulcal FLAIR-hyperintensity and leptomeningeal contrast enhancement. Occasionally these can be the dominant features with minimal to no cortical involvement. The term FLAIR-variable unilateral enhancement of the leptomeninges (FUEL) has been suggested 4.  

Due to the clinical and radiographic presentation of FLAMES possible differential diagnoses are:

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