The pituitary gland, the anterior pituitary gland, is composed of glandular cells arranged in corpuscles or enclosed in small follicles. The pituitary gland cells are divided into growth hormone cells (about 50%), prolactin cells (about 15%-25%), adrenocorticotropic cells (about 20%), thyrotropin cells (about 5%), luteinizing hormone cells and follicle stimulating hormone cells (about 10%) and large eosinophils (oncocyte). Pituitary adenoma is a common benign tumor with a population incidence of generally 1 per 100,000, with some reports as high as 7 per 100,000. Its annual incidence is 70 per 1 million women and 28 per 1 million men. The incidence of pituitary adenoma is second only to glioma and meningioma among intracranial tumors, accounting for about 10% of intracranial tumors, but the detection rate in autopsy is 20%-30%, and there is a trend of increase in recent years. Pituitary tumors are tumors that originate from pituitary gland cells and have different clinical manifestations depending on the hormone-secreting properties of the cells.