What are the main differentials for a predominantly cyst lesion in the sella?
Rathke's cleft cyst, arachnoid cyst, craniopharyngioma (adamantimonatous type), and epidermoid cyst.
There is a cystic lesion mildly expanding the sella and with a large suprasellar component that displaces the optic chiasm superiorly. The lesion has homogeneous signal, hypo on T1 and hyper on T2, and demonstrates a thin rim of enhancement, which is more bulky anteriorly presumably corresponding to an anterior displaced normal pituitary gland. No cavernous sinus invasion. The remainder imaged brain is unremarkable.