The patient eventually had a skull x-ray (for surgical planning; not for diagnosis). What feature helps you favour one of the two most likely entities over the other?
The pituitary fossa is normal in size making the mass unlikely to represent a macroadenoma, as the arise from the gland and invariably expand the fossa by the time the are this size. As such a meningioma or possibly a craniopharyngioma (papillary subtype; which are solid) are more likely.
AP and lateral views of the skull are unremarkable. The pituitary fossa is normal in size. There is no evidence of bony destruction or hyperostosis.