Brain MRI of PML in a patient with chronic lymphocytic leukemia

76-year-old patient with CLL and PML. (A) Brain MRI axial FLAIR images show hyperintense signal in left inferior parietal lobule (asterisk). Note relatively little mass effect on adjacent atrium of left lateral ventricle. Pre-contrast (B) and post-contrast (C) T1-weighted images show nonenhancing hypointensity in the inferior parietal lobule. Trace diffusion-weighted image (D) and ADC map (E) show a rim of hyperintensity along the anterior margin of the lesion (arrow) but no corresponding hypointensity on the ADC image, indicating absence of reduced diffusivity.