Legend Axial T2 images reveal a high-signal scalloped mass encasing the basilar artery and pushing on the brainstem.

Legend A sagittal T1 image (left) shows the mass and its relationship with the basilar artery and brainstem. Note how it follows fluid signal on all sequences. Also note the specific finding of restricted diffusion on diffusion weighted scans (right).

Legend Post gad images reveal no enhancement. Note the lateral displacement of the left 5th cranial nerve (left image). Key words: mri dwi tumor neoplasia

Brain Diagnosis: Epidermoid tumor