Figure 1: T1 hypointense (top row left) oval, subcortical lesion with corresponding FLAIR hyperintense signal (top row right) and faint rim of incomplete (horse-shoe) enhancement (bottom row left). Notice the mildly increased cerebral blood volume on MR perfusion imaging (bottom row right) along the medial margin. The incomplete rim of enhancement and low T1 signal is fairly classic for a tumefactive, demyelinating lesion. While perfusion can be mildly increased along the periphery of the lesion, it is often much less than would be expected with a high grade glioma.
Figure 2: Tumefactivedemyelinating lesions are often large and masslike, demonstrating FLAIR hyperintensitythroughout the lesion (top row left – sagittal, top row right, bottom row left - axial). These lesions commonly involve the corpus callosum (top row left, top row right - arrow) and are often confused for lymphoma or glioblastoma. As is common for lesions of demyelination, there is vague incomplete peripheral enhancement on post-contrast imaging (bottom row right).
- Probable autoimmune-mediated demyelination in which environmental factors affect genetically susceptible individuals
- Activated T-cells attack myelinated axons
- Variable; often initial impaired/double vision of acute optic neuritis
- Weakness, numbness, tingling, gait disturbances, multiple cranial nerve palsies
- Spinal cord symptoms in most patients
- Age of onset