Acromegaly (from Greek akros "extreme" or "extremities" an megalos "large" - extremities enlargement) is a syndrome that results when the pituitary gland produces excess growth hormone (hGH) after epiphyseal plate closure. A number of disorders may be affecting the pituitary to create this circumstance, although most commonly it involves a GH producing tumor derived from a distinct type of cells (somatotrophs) and called pituitary adenoma.