There is a large region of FLAIR/T2 hyperintensity within the right parietooccipital lobe. The more anteromedial component of the T2 signal change extends into the spenium of the corpus callosum and crosses the midline. Ill-defined peripheral nodular enhancement is demonstrated along the margins of the lesion with no enhancing component demonstrated within the corpus callosum. Despite it's size minimal mass effect is exerted on the adjacent parenchyma.
The MR spectroscopy (not shown) reveals elevated choline peaks and depressed NAA peaks. There are large lipid/lactate peaks. There is reduction in the regional perfusion (not shown). Restricted diffusion is shown only in the very peripheral portion of the lesion.
A region of ill-defined T2 hyperintensity within the central pons is of uncertain significance.
Conclusion:
The imaging features are non-specific but favour tumefactive demyelination. The alternative diagnosis is of a high-grade diffuse glioma although this is thought less likely.