Brain MRI showing bilateral, asymmetric lesions of progressive multifocal leukoencephalopathy (PML)

Bilateral but asymmetric lesions of PML in 62-year-old patient on brain MRI. Axial T2-weighted (A) and FLAIR (B) images show bilateral hyperintense lesions (asterisks) in the subcortical white matter of both inferior parietal lobules. On postcontrast axial (C) and precontrast sagittal T1-weighted (D) images, note the marked hypointensity of the subcortical white matter lesion that spares adjacent cortex. In most cases, there is no associated central or peripheral contrast-enhancement with PML.