What are your differentials?
The imaging appearances favour a Rathke's cleft cyst, although differentials would include less likely a post apoplexy macroadenoma and craniopharyngioma.
There is a lobulated lesion measuring 12 x 16 x 22 mm (AP x ML x SI) filling the sella and extending into the anterior aspect of the suprasellar cistern. This is T1 and T2 hyperintense, the T2 signal brighter than adjacent CSF. A rim of slowly enhancing tissue at the left inferolateral margin likely reflects normal enhancing residual pituitary tissue, although this has a marginal planar low T2 signal which may indicate minor calcification or chronic blood product. No definite internal nodule. The lesion displaces the infundibulum anterosuperiorly and distorts the posterior optic nerves, also displacing the chiasm superiorly. No cavernous sinus extension. Cavernous carotid flow voids are maintained. Mucoperiosteal thickening is noted throughout the imaged paranasal sinuses.