The pituitary fossa is enlarged by a mass that enhances and has a conspicuously low T2 signal. The right cavernous sinus is invaded. The right ICA is not narrowed. The optic chiasm is elevated.
Conclusion:
Although enlargement of the pituitary fossa and growth pattern is typical for a pituitary macroadenoma, the low T2 signal is unusual. Other possibilities include solitary fibrous tumours of the dura and infiltration with fibrotic tissue (e.g. IgG4 disease or Erheim Chester disease).