Pituitary macroadenomas are the most common suprasellar mass in adults, and responsible for the majority of transsphenoidal hypophysectomies. They are defined as pituitary adenomas greater than 10 mm in size and are approximately twice as common as pituitary microadenomas.
MRI is the preferred imaging modality, not only able to delineate the mass exquisitely but also clearly visualize the optic chiasm, anterior cerebral vessels and cavernous sinuses. Pituitary macroadenomas are isointense to the grey matter both on T1- and T2-weighted images. However, signal characteristics can significantly vary depending on tumor components such as hemorrhage, cystic transformation or necrosis.