# Hyperfunction of pituitary gland
**Hyperfunction of pituitary gland** is a clinical status in which one or more pituitary hormones are produced in excess, mostly caused by hormone-producing pituitary adenomas. The World Health Organization's ICD-11 classifies it under code 5A60 as a disease characterized by hypersecretion of adenohypophyseal hormones such as growth hormone, prolactin, thyrotropin, luteinising hormone, follicle stimulating hormone, or adrenocorticotropic hormone.[1](https://www.icd11-code.com/5a60/) The resulting disorders, which include acromegaly, pituitary gigantism, and [hyperprolactinaemia](https://www.edgepedia.org/hyperprolactinaemia), are treated with surgery, medication, radiation therapy, or observation depending on the hormone involved and the size and behavior of the tumor.[2](https://www.cancer.gov/types/pituitary/hp/pituitary-treatment-pdq)
| Key fact | Detail |
|---|---|
| Definition | Excessive production of one or more pituitary hormones, mostly caused by hormone-producing pituitary adenomas; ICD-11 code 5A60[1](https://www.icd11-code.com/5a60/) |
| Hormones involved | Growth hormone, prolactin, thyrotropin, luteinising hormone, follicle stimulating hormone, or adrenocorticotropic hormone[1](https://www.icd11-code.com/5a60/) |
| Subordinate codes | 5A60.0 acromegaly or pituitary gigantism; 5A60.1 hyperprolactinaemia; 5A60.2 syndrome of inappropriate secretion of antidiuretic hormone; 5A60.3 central precocious puberty[1](https://www.icd11-code.com/5a60/) |
| Adenoma hormone types | Prolactin-secreting 32–51% of pituitary adenomas, growth hormone 9–11%, ACTH 3–6%, TSH-secreting and gonadotropin-secreting under 1%[3](https://pmc.ncbi.nlm.nih.gov/articles/PMC5464431/) |
| Frequency | Clinically evident pituitary adenomas occur in approximately 1 in 1,100 persons; macroadenomas (10 mm or larger) are 48% of tumors[4](https://pubmed.ncbi.nlm.nih.gov/37097352/) |
| Surgical outcome | For Cushing disease, about 70% to 90% of people achieve remission with surgery at an experienced surgical center[5](https://www.mayoclinic.org/diseases-conditions/pituitary-tumors/diagnosis-treatment/drc-20350553) |
| Mainstay operation | Transsphenoidal microsurgery, reached through the nasal cavity, is the most widely used surgical approach[2](https://www.cancer.gov/types/pituitary/hp/pituitary-treatment-pdq) |
## Classification
ICD-11 places 5A60 within the chapter on endocrine, nutritional, or metabolic diseases, under disorders of the pituitary hormone system.[1](https://www.icd11-code.com/5a60/) The category has subordinate codes for acromegaly or pituitary gigantism (5A60.0), hyperprolactinaemia (5A60.1), the syndrome of inappropriate secretion of antidiuretic hormone (5A60.2), and central precocious puberty (5A60.3).[1](https://www.icd11-code.com/5a60/)
The category also carries exclusions, conditions coded elsewhere despite involving pituitary hormone excess. These include Cushing syndrome (5A70), overproduction of pituitary ACTH (5A70.0), [Nelson syndrome](https://www.edgepedia.org/nelson-syndrome) (5A70.3), overproduction of thyroid-stimulating hormone (4B4Y), and multiple endocrine neoplasia types 1 and 4 (2F7A.0).[1](https://www.icd11-code.com/5a60/) The WHO reference guide cites 5A60 and its exclusion of Cushing syndrome as an example of how ICD-11 presents exclusions in its content.[6](https://icdcdn.who.int/icd11referenceguide/en/refguide.pdf)
## Causes and epidemiology
The great majority of cases are caused by pituitary adenomas, benign clonal neoplasms of the neuroendocrine epithelial cells of the adenohypophysis, the hormone-producing anterior lobe of the gland.[7](https://www.ncbi.nlm.nih.gov/books/NBK425704/) Pituitary adenomas account for 14% of primary intracranial and central nervous system tumors, and their overall prevalence in the general population, combining radiographic and autopsy data, is estimated at 17%.[3](https://pmc.ncbi.nlm.nih.gov/articles/PMC5464431/) A review in Endocrine Reports estimates that pituitary adenomas occur in 10% of the population, but that fewer than one-thousandth of all pituitary adenomas cause clinically significant disease.[8](https://www.endocrine.org/journals/endocrine-reviews/clinical-biology-of-the-pituitary-adenoma)
Among adenomas, roughly half are hormone-secreting (46% to 64%) and the rest are nonfunctional.[3](https://pmc.ncbi.nlm.nih.gov/articles/PMC5464431/) Prolactin-secreting adenomas, called prolactinomas, are the most common functioning type; the Endocrine Society guideline states that they account for approximately 40% of all pituitary tumors.[9](https://academic.oup.com/jcem/article/96/2/273/2709487) [Growth hormone](https://www.edgepedia.org/growth-hormone)-secreting and ACTH-secreting adenomas are less common, and TSH-secreting and gonadotropin-secreting adenomas are rare, each under 1% of pituitary adenomas.[3](https://pmc.ncbi.nlm.nih.gov/articles/PMC5464431/)
Hyperprolactinaemia is not always tumoral. Prolactin secretion is tonically suppressed by hypothalamic dopamine, and elevation can also arise from medications, pregnancy, breast-feeding, stress, exercise, sleep, renal failure, and hypothyroidism; the Endocrine Society recommends excluding medication use, renal failure, hypothyroidism, and pituitary and parasellar tumors before attributing symptomatic hyperprolactinemia to a prolactinoma.[9](https://academic.oup.com/jcem/article/96/2/273/2709487)
## Clinical syndromes
**Growth hormone excess.** Secretion of growth hormone by a pituitary tumor causes acromegaly in adults and pituitary gigantism when it begins before the skeleton has finished growing, in the prepubertal period.[10](https://pmc.ncbi.nlm.nih.gov/articles/PMC11912844/) Growth hormone hypersecretion leads to overproduction of insulin-like growth factor 1 (IGF-1) and multisystem disease, with increased morbidity and mortality.[11](https://pmc.ncbi.nlm.nih.gov/articles/PMC10845214/pdf/CD013561.pdf) Physical findings include frontal bossing, an enlarged frontal sinus, and cutis gyrata.[12](https://www.ncbi.nlm.nih.gov/books/NBK278983/)
**Corticotroph disease.** ACTH-secreting adenomas cause [Cushing's disease](https://www.edgepedia.org/cushings-disease), which produces weight gain, truncal obesity, a "buffalo hump", enlargement of the supraclavicular fat pads, moon facies, purple striae, easy bruisability, hypertension, osteoporosis, and impaired glucose metabolism.[12](https://www.ncbi.nlm.nih.gov/books/NBK278983/) In ICD-11, Cushing syndrome and pituitary ACTH overproduction are coded separately from 5A60.[1](https://www.icd11-code.com/5a60/)
**Prolactin excess.** Women with prolactinomas classically present with amenorrhea or oligomenorrhea and galactorrhea, and most are in their childbearing years; men and women beyond their reproductive years more often have headache, visual symptoms, sexual dysfunction, and signs of decreased pituitary function.[12](https://www.ncbi.nlm.nih.gov/books/NBK278983/)
## Diagnosis
A panel of endocrinological tests can usually confirm the clinical diagnosis of a hormone-secreting pituitary adenoma. Serum growth hormone and IGF-1 levels screen for acromegaly, and failure to suppress growth hormone after an oral glucose load confirms the diagnosis.[12](https://www.ncbi.nlm.nih.gov/books/NBK278983/) An elevated age-adjusted IGF-1 level is a reliable indicator, with 90% specificity for a growth hormone-secreting pituitary adenoma.[11](https://pmc.ncbi.nlm.nih.gov/articles/PMC10845214/pdf/CD013561.pdf)
For prolactin, a single serum measurement above the upper limit of normal establishes the diagnosis of hyperprolactinemia, and dynamic testing of prolactin secretion is not recommended.[9](https://academic.oup.com/jcem/article/96/2/273/2709487) Although any macroadenoma may cause moderate prolactin elevation, levels greater than 200 ng/ml (3,600 mU/L) are highly suggestive of a prolactin-secreting adenoma; sample dilution may be needed to avoid the "hook effect", an assay artifact that can give falsely low values.[12](https://www.ncbi.nlm.nih.gov/books/NBK278983/)
For Cushing's disease, supportive findings include elevated ACTH, elevated late-night salivary or 24-hour urine free cortisol, loss of the normal diurnal variation in cortisol, and suppression of serum cortisol after high-dose but not low-dose dexamethasone. [Inferior petrosal sinus sampling](https://www.edgepedia.org/inferior-petrosal-sinus-sampling) after corticotropin-releasing hormone stimulation may be required to confirm and localize the pituitary source.[12](https://www.ncbi.nlm.nih.gov/books/NBK278983/)
## Treatment
Treatment options are surgery, radiation therapy, medical therapy, or a combination, chosen according to the tumor type, the nature of the hormonal excess, and whether the tumor extends into surrounding brain.[2](https://www.cancer.gov/types/pituitary/hp/pituitary-treatment-pdq) The goals include normalization of hormonal hypersecretion, relief of mass effect, preservation or recovery of normal pituitary function, and prevention of recurrence.[2](https://www.cancer.gov/types/pituitary/hp/pituitary-treatment-pdq) • [12](https://www.ncbi.nlm.nih.gov/books/NBK278983/) Most pituitary tumors are not cancer and may not need treatment if they cause no symptoms; in many cases regular monitoring is enough.[5](https://www.mayoclinic.org/diseases-conditions/pituitary-tumors/diagnosis-treatment/drc-20350553)
**Surgery.** The transsphenoidal microsurgical approach, which reaches the sella through the nose, is the most widely used approach and is often successful in debulking tumors even with significant suprasellar extension.[2](https://www.cancer.gov/types/pituitary/hp/pituitary-treatment-pdq) Along with acromegaly, surgery remains the first-line therapy for ACTH-secreting tumors and Cushing disease.[12](https://www.ncbi.nlm.nih.gov/books/NBK278983/) For Cushing disease, about 70% to 90% of people achieve remission when operated on at an experienced surgical center, and about 70% to 90% of people with vision problems see improvement after removal of a tumor pressing on the visual nerves.[5](https://www.mayoclinic.org/diseases-conditions/pituitary-tumors/diagnosis-treatment/drc-20350553)
**Medication and radiation.** For acromegaly, dopamine agonists, somatostatin analogs, and growth hormone receptor blockers were introduced after 1970 and can control the disease.[13](https://pubmed.ncbi.nlm.nih.gov/25572320/) [Radiation therapy](https://www.edgepedia.org/radiation-therapy) may be used after surgery or when surgery is not an option, with the beam aimed precisely so nearby healthy brain tissue receives very little radiation.[5](https://www.mayoclinic.org/diseases-conditions/pituitary-tumors/diagnosis-treatment/drc-20350553) A Cochrane review of growth hormone-secreting adenomas in adults found that the evidence comparing surgical and non-surgical management is very limited, based on eight randomized trials with 445 individuals, and that outcomes such as disease recurrence and side effects were sparsely reported.[14](https://www.cochrane.org/evidence/CD013561_surgical-and-non-surgical-procedures-management-pituitary-tumours-secrete-growth-hormones-adults)
## History
[Pierre Marie](https://www.edgepedia.org/pierre-marie) coined the term "acromegaly" in 1886 and linked it to a distinct clinical disease with a characteristic clinical picture, although he was not the first physician to give a full record of the condition; the Dutch physician Johannes Wier had preceded him.[13](https://pubmed.ncbi.nlm.nih.gov/25572320/) After Marie, pituitary enlargement was noted in almost all patients with acromegaly, and it was subsequently discovered that pituitary hyperfunction caused by a pituitary tumor was the cause.[13](https://pubmed.ncbi.nlm.nih.gov/25572320/) In 1909, [Harvey Williams Cushing](https://www.edgepedia.org/harvey-williams-cushing) introduced the concepts of "hyperpituitarism" and "hypopituitarism" and explained gigantism and acromegaly by overstimulation of growth; he was among the first to postulate growth hormone in the pituitary gland, confirming that anterior pituitary lobe hyperfunction was responsible for acromegaly.[10](https://pmc.ncbi.nlm.nih.gov/articles/PMC11912844/) The discovery of growth hormone and insulin-like growth factor I, and the demonstration of their association with hypersecretion and elevated circulating IGF-I, completed the causal account.[13](https://pubmed.ncbi.nlm.nih.gov/25572320/) From the beginning of the 20th century acromegaly could be treated by pituitary surgery or radiotherapy, and after 1970 medical therapies were added.[13](https://pubmed.ncbi.nlm.nih.gov/25572320/)
## References
1. [5A60 — Hyperfunction of pituitary gland, ICD-11](https://www.icd11-code.com/5a60/)
2. [Pituitary Tumors Treatment (PDQ®), National Cancer Institute](https://www.cancer.gov/types/pituitary/hp/pituitary-treatment-pdq)
3. [Management of hormone-secreting pituitary adenomas, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC5464431/)
4. [Tritos NA, Miller KK. Diagnosis and Management of Pituitary Adenomas: A Review. JAMA 2023;329(16):1386-1398](https://pubmed.ncbi.nlm.nih.gov/37097352/)
5. [Pituitary tumors and adenomas: Diagnosis and treatment, Mayo Clinic](https://www.mayoclinic.org/diseases-conditions/pituitary-tumors/diagnosis-treatment/drc-20350553)
6. [ICD-11 Reference Guide, World Health Organization](https://icdcdn.who.int/icd11referenceguide/en/refguide.pdf)
7. [Pathology and Pathogenesis of Pituitary Adenomas and Other Sellar Lesions, Endotext](https://www.ncbi.nlm.nih.gov/books/NBK425704/)
8. [Clinical Biology of the Pituitary Adenoma, Endocrine Reviews](https://www.endocrine.org/journals/endocrine-reviews/clinical-biology-of-the-pituitary-adenoma)
9. [Diagnosis and Treatment of Hyperprolactinemia: An Endocrine Society Clinical Practice Guideline, JCEM](https://academic.oup.com/jcem/article/96/2/273/2709487)
10. [Gigantism and Acromegaly Through History, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC11912844/)
11. [Cochrane Database of Systematic Reviews, CD013561 (GH-secreting adenomas)](https://pmc.ncbi.nlm.nih.gov/articles/PMC10845214/pdf/CD013561.pdf)
12. [Surgical Treatment of Pituitary Adenomas, Endotext](https://www.ncbi.nlm.nih.gov/books/NBK278983/)
13. [de Herder WW. The History of Acromegaly. Neuroendocrinology 2016;103(1):7-17](https://pubmed.ncbi.nlm.nih.gov/25572320/)
14. [Surgical and non-surgical procedures for management of pituitary tumours that secrete growth hormones in adults, Cochrane](https://www.cochrane.org/evidence/CD013561_surgical-and-non-surgical-procedures-management-pituitary-tumours-secrete-growth-hormones-adults)
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*Topic: Encyclopedia › Life and health › Human health and medicine › Diseases and injuries › Digestive, metabolic, and endocrine conditions › Pituitary, neuroendocrine, and multiple endocrine neoplasia*
*Initially written Oct 21, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license