tumefactive demyelination
Pronunciation: tumor-FAK-tiv
Large inflammatory demyelinating lesion that mimics brain tumor on imaging studies.
Full Definition
Tumefactive demyelination refers to large inflammatory demyelinating lesions, typically greater than 2 cm in diameter, that exhibit mass effect and enhancement patterns on neuroimaging that can closely mimic brain tumors or other space-occupying lesions. These lesions represent an uncommon presentation of demyelinating disease that can occur in multiple sclerosis, acute disseminated encephalomyelitis, or as isolated events. The term 'tumefactive' derives from the tumor-like appearance on magnetic resonance imaging, including rim enhancement, mass effect, and surrounding edema. Distinguishing features that favor demyelination over neoplasm include incomplete ring enhancement, minimal mass effect relative to lesion size, and absence of restricted diffusion. Biopsy may be necessary for definitive diagnosis when imaging features are ambiguous. These lesions often respond well to corticosteroid therapy, with significant reduction in size and enhancement typically occurring within weeks to months.
Usage
Usage note: Always compare with tumor differential and document response to anti-inflammatory therapy.
In Context
- "The large enhancing lesion was diagnosed as tumefactive demyelination rather than glioblastoma based on biopsy results." — Pathology report
- "Tumefactive demyelination showed significant improvement following high-dose corticosteroid treatment." — Treatment response note