Posterior reversible encephalopathy syndrome: High intensity on T2/FLAIR with symmetric involvement of cortex and the subcortical white matter favoring the parietal and occipital lobes. DWI is usually normal. SWI may show microhemorrhage.

Progressive multifocal leukoencephalopathy: Asymmetric involvement in periventricular and subcortical white matter with involvement of the subcortical U-fibers. Parietooccipital region and thalamus are typically affected, without mass effect and contrast enhancement.

Gliomatosis cerebri: Asymmetric involvement of white and gray matter in more than 3 lobes. DWI is usually normal, with minimal or no contrast enhancement. This term has now been excluded from the 2016 WHO tumor classification, and these malignancies are considered to be diffusely infiltrative astrocytomas.