Acromegaly (; from Greek άκρος akros "extreme" or "extremities" and μεγάλος megalos "large") is a syndrome that results when the anterior pituitary  gland produces excess growth hormone (GH) after epiphyseal plate closure at puberty. A number of disorders may increase the pituitary's GH output, although most commonly it involves a GH-producing tumor called pituitary adenoma, derived from a distinct type of cell (somatotrophs).