In clinical practice pituitary tumors are classified into pituitary microadenomas and pituitary macroadenomas according to their size. A pituitary microadenoma is a pituitary tumor with a tumor diameter of <10 mm, while a pituitary macroadenoma is a pituitary tumor with a tumor diameter of >10 mm. The CT presentation of pituitary macroadenoma is a tumor >10mm in diameter with a cross-sectional pattern of round, lobulated or irregular shape. CT scan may be isointense, slightly hyperdense or hypointense with uniform or heterogeneous density. On CT scan, the lesion may be homogeneous or heterogeneous, with a few cases of ring-like enhancement. If the tumor compresses the pterygoid saddle, it will lead to enlargement of the pterygoid saddle and saddle subdivision. The lesion may push the optic cross or compress the third ventricle upward, involve the cavernous sinus or encircle the internal carotid artery to both sides, protrude into the pterygoid sinus downward, and compress the brainstem backward.