Legend Parasagittal T1-WI demonstrates a large heterogeneous, lobulated mass involving portions of the clivus and parasellar structures. Axial T2-WI demonstrates an extraaxial, heterogeneous, lobulated mass. There is suggestion that the epicenter may be near the junction of the posterior clinoid process and the clivus. Realizing that the sphenooccipital suture is located here is a potential clue to the correct diagnosis. Note the T2 hyperintensity arranged in a lobular fashion. The supraclinoid carotid is both displaced and encased.

Legend Axial FLAIR, axial T2, and coronal T1-WI demonstrate significant mass effect on the medial right temporal lobe and right cerebral peduncle.

Legend T1-WIs after gadolinium and fat saturation nicely demonstrate the typical peripheral enhancement in a lobular fashion. Axial CT better demonstrates the nature of the lesion. Note that the lesion appears to contain a matrix of arcs and whirls.

Legend MIP image from TOF MRA demonstrates reduction in caliber of the distal right cavernous and supraclinoid carotid. Note how the right distal carotid, MCA, ACA, and PCA are all attenuated and stretched. Injection of the right internal carotid demonstrates narrowing secondary to encasement. The ophthalmic artery remains patent. The mass is mildly hypervascular. Key words: mri mra angiogram angiography tumor neoplasia

Brain Diagnosis: Chondrosarcoma of skull base