What is acromegaly?
Acromegaly is a very rare disorder caused, in most cases, by a tumor of the pituitary gland that produces too much growth hormone (GH). Nearly all pituitary tumors, including those that cause acromegaly, are benign, as opposed to malignant. However, they can become quite large and expand beyond the normal confines of the pituitary gland. Rarely, acromegaly can be caused by a tumor located in other areas of the body.
Pituitary gland location

Head image from Microsoft Digital Library