Ectopic Acromegaly Caused by Peripheral Ectopic Growth Hormone Hypersecretion: A Case Report and Literature Review

Acromegaly is most commonly caused by a growth hormone (GH)-secreting pituitary adenoma. In exceptionally rare circumstances, pituitary imaging fails to reveal an adenoma, thereby raising suspicion for ectopic acromegaly. Here, we report the case of a 70-year-old patient who presented for evaluation of headaches and glycemic control. Investigations confirmed ectopic acromegaly due to peripheral GH secretion. The source of GH secretion was a probable digestive neuroendocrine tumor (NET). Given the patient's refusal of surgical intervention, treatment with a somatostatin analog was initiated, resulting in glycemic control consistent with the targets defined according to the patient's age and comorbidities. Insulin-like growth factor 1 (IGF-1) levels subsequently normalized. The diagnosis of GH-secreting ectopic acromegaly is based on correlating clinical manifestations with biochemical evidence of GH excess and appropriate imaging studies. Management is largely driven by surgical removal of the responsible lesion when possible, complemented by somatostatin analogs when indicated. The epidemiology and pertinent literature of this uncommon condition are discussed.