IGF1 and neuroendocrine neoplasm: Acromegaly is a rare disease caused by the elevated and autonomous secretion of growth hormone (GH) from a pituitary somatotroph tumor or neuroendocrine tumors, and the subsequent hypersecretion of insulin-like growth factor I (IGF-I) in peripheral tissues. Excess GH and IGF-I cause several chronic and systemic complications that impact mortality, morbidity, and quality of life in patients with acromegaly.