Anaplastic pituitary adenomas that may cause elevated prolactin. Anaplastic adenomas are a type of pituitary adenoma that does cause signs of elevated prolactin during growth, while anaplastic pituitary adenomas may also show elevated prolactin due to the pituitary stalk effect. However, this does not mean that all patients with growing pituitary adenomas show signs of elevated prolactin, and there are some patients who experience a decrease. Elevated prolactin cannot be ruled out due to other factors, such as polycystic ovary syndrome, or due to autoimmune diseases, which may also cause this condition, and patients are advised to find out the cause. Patients with non-functional pituitary adenomas should actively cooperate with the treatment, so as not to wait until the tumor is large enough to compress the optic nerve, resulting in visual impairment or tumor stroke.