CT and MRI 'ring sign' may be due to demyelination: diagnostic pitfall

Area of Science:

• Neurology
• Neuroimaging
• Pathology

Background:

• Acute demyelinating encephalomyelitis (ADEM) is an immune-mediated inflammatory demyelinating disease of the central nervous system.
• Typical ADEM presentations involve multifocal white matter lesions, often with incomplete ring enhancement.

Observation:

• This case details a rare presentation of ADEM with multiple, discrete ring-enhancing lesions observed on both CT and MRI.
• These imaging findings were initially suggestive of differential diagnoses such as brain abscesses or primary brain tumors.

Findings:

• The pathological examination confirmed ADEM, despite the atypical imaging characteristics.
• The presence of multiple ring-enhancing lesions in ADEM is an uncommon phenomenon, challenging initial diagnostic interpretations.

Implications:

• This case underscores the importance of considering ADEM in the differential diagnosis of ring-enhancing brain lesions, even with atypical imaging features.
• Accurate diagnosis is crucial for appropriate treatment and management of ADEM, distinguishing it from infectious or neoplastic processes.