FIG 4. Case 2: 22-year-old woman with disease progression.

A, Initial coronal contrast-enhanced T1-weighted MR image with focal enhancement in the left sylvian fissure (arrow).

B, Follow-up study 2 weeks later shows a new small focus of abnormal meningeal enhancement (arrow) on the medial aspect of the uncus.

C and D, Another week later, there is marked progression of disease to diffusely involve the basilar cisterns (arrows) as well as the course of the middle cerebral arteries (arrowheads).