GH Adenoma (Acromegaly)
A growth hormone (GH)-secreting pituitary tumor leads to excess GH and IGF-1 in the blood. In adults it produces acromegaly, marked by gradual enlargement of the hands, feet and face; in children, before the growth plates close, it causes gigantism. Although it is a benign pituitary neuroendocrine tumor (PitNET), untreated disease produces important systemic complications.
Última actualización: 2026-06-07
Definition
GH adenoma (somatotropinoma) is a benign tumor arising from the somatotroph cells of the anterior pituitary that secretes excess growth hormone (GH). In the 2022 WHO classification it is defined as a PIT1-lineage pituitary neuroendocrine tumor (PitNET). Excess GH increases hepatic production of IGF-1 (insulin-like growth factor-1); most of the growth effects on tissues are mediated by IGF-1.
Epidemiology
GH adenoma is among the more common functional pituitary tumors, after prolactinoma. It is usually diagnosed in the fifth decade, with a roughly equal sex distribution. Because the physical changes of acromegaly develop very slowly, there is typically an average delay of several years between the first symptoms and diagnosis. A substantial proportion of tumors are macroadenomas (10 mm or larger) at diagnosis.
Symptoms
In acromegaly, symptoms develop insidiously over years. Enlargement of the hands and feet (increasing ring and shoe size), coarsening of facial features, a protruding lower jaw (prognathism), spacing of the teeth, enlargement of the tongue and deepening of the voice are typical; comparison with old photographs aids diagnosis. Common associated problems include joint pain, increased sweating, carpal tunnel syndrome and obstructive sleep apnea. Large tumors may cause visual field loss from optic chiasm compression, headache and deficiency of other pituitary hormones.
Systemic Complications
Untreated acromegaly affects many organs—above all the cardiovascular system—and can shorten life expectancy. Hypertension, left ventricular hypertrophy, valvular heart disease and arrhythmias are common; cardiovascular disease is the leading cause of death. In addition, diabetes or impaired glucose tolerance, obstructive sleep apnea, joint disease and an increased number of colon polyps may occur; colonoscopy is therefore recommended at diagnosis and during follow-up.
Diagnosis
Diagnosis is biochemical. The screening test is the IGF-1 level interpreted by age and sex, since IGF-1 is a more stable marker than GH. For confirmation, assessing GH suppression during an oral glucose tolerance test (OGTT) is the gold standard: in healthy individuals a glucose load suppresses GH, whereas in acromegaly suppression fails to occur. Contrast-enhanced thin-slice pituitary MRI is used to image the tumor and to assess cavernous sinus invasion and suprasellar extension. When optic chiasm compression is suspected, visual field testing and evaluation of the other pituitary hormonal axes are required.
Treatment Options
In most cases first-line treatment is endoscopic transsphenoidal surgery; remission rates are higher for small tumors and those without cavernous sinus invasion. When surgery does not achieve adequate control or the patient is not a surgical candidate, medical therapy is used. Somatostatin receptor ligands (octreotide, lanreotide) are the first-line medical option, suppressing GH release and modestly shrinking the tumor. In resistant cases, the GH receptor antagonist pegvisomant (combined with a somatostatin analogue when needed), the second-generation somatostatin ligand pasireotide in selected cases, or a dopamine agonist as an adjunct may be used. Radiotherapy (stereotactic radiosurgery or fractionated) is applied for progressive tumors not responding to surgery and medical therapy.
Prognosis
Acromegaly is caused by a benign tumor, but if the hormonal excess is left untreated it can raise mortality through cardiovascular, respiratory and metabolic complications. With early diagnosis and effective normalization of GH/IGF-1 levels, the mortality risk approaches that of the general population. In patients who achieve biochemical remission the recurrence risk is low, but lifelong follow-up is required in those with residual tumor. Care is planned by a multidisciplinary team; outcomes vary from patient to patient and no outcome can be guaranteed.
Referencias
- Greenberg MS. Greenberg's Handbook of Neurosurgery. 10th ed. Thieme; 2023:870.
- Winn HR, ed. Youmans Neurological Surgery. 6th ed. Saunders; 2011:1479.
- Asa SL, et al. Overview of the 2022 WHO Classification of Pituitary Tumors. Endocr Pathol. 2022.
- Katznelson L, et al. Acromegaly: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2014.
Este artículo es informativo y no sustituye un examen médico. Las decisiones de diagnóstico y tratamiento son individuales.