GH1 and pituitary gland adenoma: Our patient, an elderly male, presented with classical features of acromegaly and was found to have elevated IGF-1 but normal levels of GH, Prolactin, ACTH, and elevated serum cortisol, effectively excluding the pituitary adenoma, hypothalamic tumors secreting growth-hormone-releasing hormone (GHRH), and nonendocrine tumors causing ectopic secretion of GH or GHRH.