There are two types of pituitary adenomas, one is called a functional adenoma and the other is called a nonfunctional adenoma. Functional adenoma is short for functional pituitary adenoma, and whenever it is a functional adenoma it refers to a functional pituitary adenoma. Functional is a pituitary adenoma because some cells, some pituitary adenomas, secrete hormones, such as prolactin, growth hormone or adrenocorticotropic hormone, from overgrown pituitary cells. If these hormones are secreted in excessive amounts, the patient will have many endocrine symptoms. If lactogen is secreted in excessive amounts, the female patient will have menopause, overflow of breast milk, and will have milk when not breastfeeding. In male patients, there will be hypogonadism, hypogonadism, infertility, and even male feminization and fair skin condition. If growth hormone production is particularly high, adolescents will develop gigantism, being unusually tall, exceeding the proportions of their parents’ stature. If growth hormone adenoma occurs in adults, they will develop acromegaly, which is thick hands and feet, thick lips, thick nose, large nose, wide forehead, and large jaw. This type of pituitary adenoma that causes endocrine symptoms is called a functional adenoma. It is different from non-functional adenoma, because patients with non-functional adenoma mainly do not have endocrine symptoms, but only have symptoms due to pressure on the surrounding optic nerves, nerves and brain nerves caused by the increase of tumor size.