Figure 2b. Patient 5. Leptomeningeal involvement with lymphomatoid granulomatosis in 37-year-old man. Transverse (a, b) precontrast and (c, d) postcontrast T1-weighted MR images (400/9) show abnormal enhancement in the leptomeninges (arrows) of the suprasellar region. Slight dilatation of the temporal horns is also present. (e) Transverse postcontrast T1-weighted MR image (400/9) of the posterior fossa shows enhancement and increased thickness of the leptomeninges in the cerebellomedullary cisterns bilaterally and choroid plexus involvement in the foramen of Luschka (arrows) on the left. (f) Transverse fluid-attenuated inversion-recovery MR image (10 000/137) of the posterior fossa after intravenous contrast material administration demonstrates abnormally increased signal intensity in the left internal auditory canal (short arrow), which is indicative of leptomeningeal inflammation, and also involves the seventh and eighth cranial nerves. There is edema (long arrow) in the left cerebellar peduncle and adjacent pons.