What do meningiomas often do to the arteries they encase, which macroadenomas do not?
Significantly narrow the lumen.
A large avidly enhancing sellar/parasellar and suprasellar mass is evident. It measures 3.9 x 3.8 x 3.1 cm. The lesion invades the sphenoid bone, filling most of the right sphenoid sinus but also involving the left. It also invades into the base of the pterygoid process on the right and into the adjacent apex of the petrous temporal bone. Posteriorly it invades through the right side of the clivus into the prepontine cistern. High T1 signal material within the remaining sphenoid sinus may represent proteinaceous or haemorrhagic fluid.
The lesion is intimately related to the right ICA, from the posterior genu of the cavernous ICA, enveloping it in the cavernous sinus (and invading the cavernous sinus) and closely related to the supraclinoid ICA to just before the bifurcation. Enhancement is still noted within the internal carotid artery.
In the suprasellar region it abuts and deforms the optic chiasm and adjacentoptic nerves. A further superior projection which is high T1 signal intrinsically (?haemorrhage) passes in the vicinity of the right oculomotor nerve, close to the cavernous sinus, and may impinge it. Anteriorly the lesion reaches close to the orbital apex.