This disorder results when a benign pituitary adenoma causes excessive growth hormone (GH) secretion. Ectopic GH secretion is extremely rare but can be seen with bronchial carcinoid tumors. The clinical symptoms are varied and include hyperhydrosis, dental malocclusion, carpal tunnel syndrome, multiple skin tags, recurrent colon polyps, deepening of the voice, macroglossia, impotence, obstructive sleep apnea, organomegaly, oligomenorrhea/amenorrhea, and type II diabetes mellitus. Physical findings include forehead frontal bossing, enlarged and coarse facial features, prognathism (abnormal forward displacement of the mandible with resultant underbite), an increase in the gaps between individual teeth, oily skin, increasing size of the hands and feet, hypertension, arthralgia, and visual field deficits. Life expectancy is shortened secondary to an increased incidence of cardiovascular disease, hypertrophic cardiomyopathy, and colon cancer; however, therapy which reverses elevated GH and insulin-like growth factor-1 (IGF-1) levels improves outcomes.

Since GH secretion is variable, it is not a reliable screening test. When acromegaly is suspected, screening is performed using the serum IGF-1 level determination. If the IGF-1 level is elevated, then confirmation is determined via GH determinations during a 2 hour glucose tolerance test with an inability to suppress GH levels to less than 1 ng/mL being diagnostic. Since most cases are secondary to a pituitary adenoma with ectopic sources being rare, an MRI evaluation of the pituitary is the next step when the glucose tolerance test is consistent with a diagnosis of acromegaly.

The first step in therapy is to debulk the tumor in the pituitary via transphenoidal sinus surgery. Surgical efficacy is determined by reassessing GH and IGF-1 levels at 2 and 4 months after surgery with normalization of the levels being indicative of a cure. Microadenomas have better chances of cure than macroadenomas. If levels remain elevated after surgical intervention, then pharmacotherapy with either somatostatin analogs (octreotide), dopamine agonists (bromocriptine or cabergoline), or GH receptor antagonists (pegvisomant) is necessary. Colon polyp/cancer screening should be performed via colonoscopy.