“Acromegaly (called gigantism in children) is a rare condition in which the whole body or parts of the body, particularly the hands and feet, grow larger than normal. More than 95 percent of all cases of acromegaly are the result of a growth hormone–secreting pituitary adenoma.

Growth hormone–secreting pituitary adenomas begin in the somatotropic cells of the pituitary gland. Also called GH, the growth hormone secreted by these tumors triggers the liver to produce insulin-like growth factor 1, or IGF-1. IGF-1 is involved in bone and tissue growth, metabolism, and other processes of the body. When the body produces too much IGF-1, it leads to a range of symptoms known as acromegaly.”

Memorial Sloan Kettering Center (Acromegaly (Growth Hormone–Secreting Pituitary Adenomas) | Memorial Sloan Kettering Cancer Center)