On imaging, this would be called a pituitary macroadenoma more than 99.9% of the time.

Craniopharyngioma and, in this age group, metastasis, can be considered in the differential. The fact that the adenohypophysis and stalk are displaced anteriorly is unusual, but would probably not be sufficient to sway the diagnostician towards other extremely rare pituitary gland tumors.

The tumor has nevertheless succeeded in distracting the radiologists into missing the ACom aneurysm on multiple studies.