Trusted medical expertise in seconds.

Access 1,000+ clinical and preclinical articles. Find answers fast with the high-powered search feature and clinical tools.

Try free for 5 days
Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer.

Pituitary adenoma

Last updated: September 9, 2021

Summarytoggle arrow icon

Pituitary adenomas (also known as pituitary neuroendocrine tumors) are benign tumors that arise sporadically from the anterior pituitary gland. They are classified as either microadenomas or macroadenomas according to their size, and as either secretory (functional) or nonsecretory (nonfunctioning) according to their ability to secrete hormones. Secretory adenomas produce the pituitary hormone of the cell type from which they arise, which results in a state of hyperpituitarism. Nonsecretory macroadenomas can destroy the surrounding normal pituitary tissue, which results in hypopituitarism. Additionally, large macroadenomas compress the optic chiasm; therefore, patients may present with signs of mass effect such as bitemporal hemianopsia. MRI sella with IV contrast is the gold standard imaging method for the pituitary and should reveal any intrasellar masses. Pituitary hormone assays are used to evaluate patients for endocrine abnormalities, and perimetry is used to identify visual field defects. Transsphenoidal hypophysectomy is the first-line therapy for most patients with symptomatic pituitary adenomas; patients with nonsecretory microadenomas generally only require follow-up (until they become symptomatic), and prolactin-producing pituitary adenomas (prolactinomas) should be initially treated with dopamine agonists (e.g., cabergoline, bromocriptine). Pituitary irradiation is indicated in recurrent pituitary adenomas and/or if surgical therapy is contraindicated.

Epidemiological data refers to the US, unless otherwise specified.

Secretory pituitary adenomas
Origin

Relative frequency (as a percentage of all pituitary adenomas)

Pathophysiology
Lactotroph adenoma (prolactinoma) [6]
  • ∼ 40%
Somatroph adenoma
  • 10–15%
Corticotroph adenoma (Cushing disease)
  • ∼ 5%
Thyrotroph adenoma
  • ∼ 1%
Gonadotroph adenoma
  • Rare

Prolactinomas are the most common pituitary adenomas.

Type Secretory adenomas Nonsecretory adenomas [5]
Microadenomas
  • Mostly asymptomatic
Macroadenomas

The symptoms associated with pituitary adenomas depend on the size of the tumor and whether the tumor produces hormones.

Approach

The diagnostic approach varies according to clinical presentation.

Diagnostic approach for a suspected pituitary adenoma [7][8][9][10]
Presentation Initial evaluation Further evaluation
Symptoms of mass effect to the pituitary
Symptoms of hypopituitarism or hyperpituitarism
  • If pituitary endocrine dysfunction is confirmed: imaging studies
Pituitary incidentaloma [8]
  • Complete clinical assessment
  • MRI sella if the mass was initially discovered using another imaging method

In patients with endocrine dysfunction, order hormone assays before imaging to prevent overdiagnosis of pituitary incidentalomas. [10]

Hormone assays [7][8][9]

Indications for testing

  • First-line tests for all patients with symptomatic endocrine dysfunction
  • Pituitary mass detected on imaging
  • Prior to planned pituitary surgery

Initial studies

  • Choice of studies
    • Symptomatic patients: Studies are chosen according to clinical presentation.
    • Asymptomatic patients: general screening
  • Interpretation
Initial hormone studies for suspected pituitary endocrine dysfunction
Symptoms Initial studies
Asymptomatic patients [9]
Hyperprolactinemia
Hypogonadism or absent lactation
Hyperthyroidism or hypothyroidism
Hypercortisolism
Adrenal insufficiency
Acromegaly or gigantism
  • IGF-1
  • For further information, see “Diagnostics” in “Acromegaly.”

Patients with pituitary incidentalomas should be evaluated for hypopituitarism and hormonal hypersecretion syndromes. [8]

About a third of patients with pituitary adenomas have associated hypopituitarism; consider screening for hormone deficiencies in all patients with a pituitary mass. [9]

Imaging studies [12][13]

Additional investigations

Visual defects may be present even in asymptomatic patients with a pituitary adenoma; consider early referral for visual field testing even in the absence of visual symptoms. [9]

Approach [7][8][9]

  • Assess patients for life-threatening and sight-threatening complications.
    • Stabilize patients with acute hormonal imbalances.
    • Refer patients with severe vision loss or altered mental state to neurosurgery urgently.
  • Refer all patients to endocrinology.
Initial treatment of pituitary adenomas [7][8][9]
Tumor type First-line treatment

Prolactinomas (symptomatic or macroadenomas)

Pharmacotherapy

Secretory adenomas (except prolactinomas)

Surgery

Symptomatic nonsecretory adenomas

Asymptomatic microprolactinomas

Observation

Asymptomatic nonsecretory adenomas

The management of patients with pituitary incidentalomas is the same as for those with any other pituitary adenoma. [7][8]

Treat patients with secretory incidentalomas according to tumor type, and treat patients with nonsecretory incidentalomas if symptoms of mass effect are present. [7][8]

Pituitary adenomas may bleed spontaneously, causing pituitary apoplexy (i.e., pituitary tumor apoplexy); this manifests with severe headaches, visual symptoms, cardiovascular collapse, and/or acute secondary adrenal insufficiency. [10]

Initial stabilization

Patients may be acutely unwell secondary to hormonal alterations; treat aggressively before starting definitive management.

Do not delay hydrocortisone treatment in patients with adrenal crisis or myxedema coma.

Surgical management [7][8][9][10]

Transsphenoidal hypophysectomy can alter ADH secretion, causing transient or permanent central DI and/or SIADH. In some patients, these alterations can occur sequentially in a biphasic pattern (i.e., DI followed by SIADH), or less frequently, in a triphasic pattern (i.e., DI followed by SIADH followed by DI). [22]

Following transsphenoidal resection and/or pituitary irradiation, patients may develop hypopituitarism and potentially require lifelong hormone replacement therapy.

Pharmacotherapy [7]

Observation

  • Indications
    • Asymptomatic microprolactinomas
    • Asymptomatic nonsecretory adenomas
Observation strategies for asymptomatic nonsecretory pituitary adenomas [7][8]
Study Follow-up intervals
Nonsecretory incidentalomas Asymptomatic prolactinoma
Imaging studies (MRI)
  • Macroadenomas: Perform at 6 months and yearly thereafter.
  • Microadenomas: Perform every 1–2 years. [8]
  • Perform only if symptoms develop or prolactin levels increase.
Hormone assays
  • Macroadenomas: Assess for hypopituitarism at 6 months and yearly thereafter.
  • Microadenomas: No hormone assays are required if the patient is asymptomatic and MRI remains unchanged compared with baseline.
  • Every 6–12 months
Visual field testing

The differential diagnoses listed here are not exhaustive.

  1. Scheithauer BW, Gaffey TA, Lloyd RV, et al. Pathobiology of Pituitary Adenomas and Carcinomas. Neurosurgery. 2006; 59 (2): p.341-353. doi: 10.1227/01.neu.0000223437.51435.6e . | Open in Read by QxMD
  2. Aflorei ED, Korbonits M. Epidemiology and etiopathogenesis of pituitary adenomas. J Neurooncol. 2014; 117 (3): p.379-394. doi: 10.1007/s11060-013-1354-5 . | Open in Read by QxMD
  3. Daly AF, Tichomirowa MA, Beckers A. The epidemiology and genetics of pituitary adenomas. Best Practice & Research Clinical Endocrinology & Metabolism. 2009; 23 (5): p.543-554. doi: 10.1016/j.beem.2009.05.008 . | Open in Read by QxMD
  4. Beckers A, Aaltonen LA, Daly AF, Karhu A. Familial Isolated Pituitary Adenomas (FIPA) and the Pituitary Adenoma Predisposition due to Mutations in the Aryl Hydrocarbon Receptor Interacting Protein (AIP) Gene. Endocr Rev. 2013; 34 (2): p.239-277. doi: 10.1210/er.2012-1013 . | Open in Read by QxMD
  5. Ntali G, Wass JA. Epidemiology, clinical presentation and diagnosis of non-functioning pituitary adenomas. Pituitary. 2018; 21 (2): p.111-118. doi: 10.1007/s11102-018-0869-3 . | Open in Read by QxMD
  6. Molitch ME. Diagnosis and Treatment of Pituitary Adenomas. JAMA. 2017; 317 (5): p.516. doi: 10.1001/jama.2016.19699 . | Open in Read by QxMD
  7. Freda PU, Beckers AM, Katznelson L, et al. Pituitary Incidentaloma: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2011; 96 (4): p.894-904. doi: 10.1210/jc.2010-1048 . | Open in Read by QxMD
  8. Lake MG, Krook LS, Cruz SV. Pituitary adenomas: an overview.. Am Fam Physician. 2013; 88 (5): p.319-27.
  9. Melmed S, Polonsky KS, Larsen PR, Kronenberg HM. Williams Textbook of Endocrinology. Elsevier ; 2016
  10. Iglesias P, Diez JJ. Macroprolactinoma: a diagnostic and therapeutic update. QJM. 2013; 106 (6): p.495-504. doi: 10.1093/qjmed/hcs240 . | Open in Read by QxMD
  11. Chen CC, Carter BS, Wang R, et al. Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Preoperative Imaging Assessment of Patients With Suspected Nonfunctioning Pituitary Adenomas. Neurosurgery. 2016; 79 (4): p.E524-E526. doi: 10.1227/neu.0000000000001391 . | Open in Read by QxMD
  12. Burns J, Policeni B, Bykowski J, et al. ACR Appropriateness Criteria® Neuroendocrine Imaging. J Am Coll Radiol. 2019; 16 (5): p.S161-S173. doi: 10.1016/j.jacr.2019.02.017 . | Open in Read by QxMD
  13. Boellis A, di Napoli A, Romano A, Bozzao A. Pituitary apoplexy: an update on clinical and imaging features. Insights into Imaging. 2014; 5 (6): p.753-762. doi: 10.1007/s13244-014-0362-0 . | Open in Read by QxMD
  14. Newman SA, Turbin RE, Bodach ME, et al. Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Pretreatment Ophthalmology Evaluation in Patients With Suspected Nonfunctioning Pituitary Adenomas. Neurosurgery. 2016; 79 (4): p.E530-E532. doi: 10.1227/neu.0000000000001388 . | Open in Read by QxMD
  15. Raverot G, Burman P, McCormack A, et al. European Society of Endocrinology Clinical Practice Guidelines for the management of aggressive pituitary tumours and carcinomas. Eur. J. Endocrinol. 2018; 178 (1): p.G1-G24. doi: 10.1530/eje-17-0796 . | Open in Read by QxMD
  16. Sheehan J, Lee C-C, Bodach ME, et al. Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline for the Management of Patients With Residual or Recurrent Nonfunctioning Pituitary Adenomas. Neurosurgery. 2016; 79 (4): p.E539-E540. doi: 10.1227/neu.0000000000001385 . | Open in Read by QxMD
  17. Varlamov EV, McCartney S, Fleseriu M. Functioning Pituitary Adenomas – Current Treatment Options and Emerging Medical Therapies. Eur Endocrinol. 2019; 15 (1): p.30. doi: 10.17925/ee.2019.15.1.30 . | Open in Read by QxMD
  18. Ji Y, Vogel RI, Lou E. Temozolomide treatment of pituitary carcinomas and atypical adenomas: systematic review of case reports. Neurooncol Pract. 2015; 3 (3): p.188-195. doi: 10.1093/nop/npv059 . | Open in Read by QxMD
  19. Inder WJ, Hunt PJ. Glucocorticoid replacement in pituitary surgery: guidelines for perioperative assessment and management.. J Clin Endocrinol Metab. 2002; 87 (6): p.2745-50. doi: 10.1210/jcem.87.6.8547 . | Open in Read by QxMD
  20. Ausiello JC, Bruce JN, Freda PU. Postoperative assessment of the patient after transsphenoidal pituitary surgery. Pituitary. 2008; 11 (4): p.391-401. doi: 10.1007/s11102-008-0086-6 . | Open in Read by QxMD
  21. Kuo JS, Barkhoudarian G, Farrell CJ, et al. Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Surgical Techniques and Technologies for the Management of Patients With Nonfunctioning Pituitary Adenomas. Neurosurgery. 2016; 79 (4): p.E536-E538. doi: 10.1227/neu.0000000000001390 . | Open in Read by QxMD
  22. Lamas C, del Pozo C, Villabona C. Clinical guidelines for management of diabetes insipidus and syndrome of inappropriate antidiuretic hormone secretion after pituitary surgery. Endocrinol Nutr. 2014; 61 (4): p.e15-e24. doi: 10.1016/j.endoen.2014.03.010 . | Open in Read by QxMD
  23. Carroll TB, Peppard WJ, Herrmann DJ, et al. Continuous Etomidate Infusion for the Management of Severe Cushing Syndrome: Validation of a Standard Protocol. J Endocr Soc. 2018; 3 (1): p.1-12. doi: 10.1210/js.2018-00269 . | Open in Read by QxMD
  24. Melmed S, Casanueva FF, Hoffman AR, et al. Diagnosis and Treatment of Hyperprolactinemia: An Endocrine Society Clinical Practice Guideline. The Journal of Clinical Endocrinology & Metabolism. 2011; 96 (2): p.273-288. doi: 10.1210/jc.2010-1692 . | Open in Read by QxMD