“Gigantism is a serious condition that is nearly always caused by an adenoma, a tumor of the pituitary gland. Gigantism occurs in patients who had excessive growth hormone in childhood. The pituitary tumor cells secrete too much growth hormone (GH), leading to many changes in the body.  Gigantism usually presents in childhood or young adulthood. If a pituitary tumor that secretes growth hormone develops after the bone growth plates fuse, the result is acromegaly.”

UCLA Health Ed.