Inflammatory Demyelinating Pseudotumor
As the name suggests is a demyelinating process, typically acute and fulminant with mass effect. The condition mimics tumor on imaging and pathology.
The key to diagnosis is the enhancement pattern - peripheral, incomplete, and often poorly defined or 'wispy'.
Pathological features include:
- Well defined borders
- Uniform distribution of foamy macrophages
- No coagulative necrosis
- Sheets of gemistocytic astrocytes with well formed processes
- Perivascular chronic inflammatory cell infiltration
- Absence of myelin with preservation of axons