What is the differential for this mass?
The differential is relatively broad and includes: pituitary macroadenoma, pituitary metastasis, papillary craniopharyngioma, meningioma, infiltrative / inflammatory process (e.g. lymphocytic hypophysitis).
What features are atypical for a macroadenoma?
The sella is not particularly enlarged (best seen in sagittal projection) and the dorsum appears eroded. Additionally there is dural thickening and the margins of the mass are less well defined than is usually the case in macroadenomas.
There is a 13 x 24 x 18 mm (AP x trans x CC) sellar and suprasellar mass. It is intermediate in signal intensity pre-contrast. There is avid post-contrast enhancement except for its a few small nonenhancing foci. No diffusion restriction is appreciated. The floor of the sella flattened and remodelled.
The mass compresses the optic chiasm against the hypothalamus, splaying the optic nerves. The cavernous internal carotid arteries are displaced medially, but remain normal in calibre. The left cavernous sinus is bulky with prominent enhancing tissue superiorly suspicious for tumour invasion. The margins of the tumour are ill-defined with irregular enhancement extending into the hypothalamic region as well as onto the surface of the tent.
No gross abnormality is detected in the remainder of the imaged brain, but please note that this study has been targeted to the pituitary, and as such the whole brain has not been imaged.