This patient went on to have a craniotomy and clipping and resection of the aneurysm. 

Thrombosed pituitary region aneurysms are relatively common and usually pose no problem in diagnosis. Occasionally however a thrombosed aneurysm can have unusual signal characteristics and may be mistaken for a solid or cystic mass such as a craniopharyngioma. Clearly, such a mistake can have disastrous consequences, particularly if transsphenoidal surgery is performed. As such a healthy habit to adopt is to ask oneself the question "could this be an aneurysm?" for all pituitary region masses.