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Pituitary Adenoma

Last Updated: Mar 1, 2019


Pituitary adenomas are benign (noncancerous) tumors of the pituitary gland - a small structure located behind the eyes, beneath the brain. Most pituitary tumors are benign, meaning that they do not spread to distant locations in the body. Cancerous pituitary tumors are extremely rare.

The pituitary gland is a principal part of the endocrine system (the set of glands and organs that produce hormones). The pituitary is called the “master endocrine gland,” because it produces specific hormones that control the activities of other endocrine glands and organs in the body.

Pituitary adenomas usually develop in older adults, but they may occur in children. These tumors are very common, occurring in up to 20% of adults. Although most pituitary adenomas are harmless, some cause serious problems. Typically, a pituitary adenoma develops in the anterior pituitary, and its impact is determined by its size and whether it secretes hormones.

Types of Pituitary Adenomas

Classification of Functional Pituitary Adenomas


The underlying cause of pituitary adenomas is unknown, and there are no lifestyle or environmental factors that increase a person’s risk of developing this condition. Rare cases are linked to inherited genetic syndromes.

pituitary gland shown in a cross-section of the brain


The signs and symptoms of pituitary adenomas correlate with the tumor size and whether excess hormone is secreted. The onset of symptoms is gradual and early symptoms may go unnoticed for years.

Prolactin-Secreting Pituitary Adenoma (Prolactinoma)

Signs and symptoms in females:

Signs and symptoms in males:

Growth Hormone-Secreting Pituitary Adenoma

Signs and symptoms of excess GH in adults (acromegaly):

Signs and symptoms of excess GH In children (gigantism):

Adrenocorticotropic Hormone (ACTH)-Secreting Pituitary Adenoma

Excess ACTH stimulates the adrenal glands to overproduce cortisol (Cushing’s disease). Normally, cortisol maintains blood pressure and helps the body react to stressful conditions; however, too much cortisol disrupts numerous bodily functions.

Symptoms of Cushing’s disease:

Thyroid-stimulating Hormone (TSH)-Secreting Pituitary Adenoma

Excess TSH stimulates the thyroid to produce too much thyroid hormone (hyperthyroidism) and abnormally accelerates the body’s metabolism.

Symptoms of hyperthyroidism:

Gonadotropin-Secreting Pituitary Adenoma

Excess gonadotropins (LH and FSH) disrupt reproductive processes.



Large pituitary adenomas may cause headaches, nausea, and vomiting. Compression of the optic chiasm causes loss of peripheral vision. Injury to the posterior pituitary impairs antidiuretic hormone (ADH) production (a condition known as diabetes insipidus) and leads to excess urination, dehydration, and thirst. Additional pituitary hormone deficiencies cause infertility.


Functional microadenomas are tiny, but they cause problems by secreting excessive hormones. Conversely, small, asymptomatic nonfunctional adenomas (so-called incidentalomas) are usually found on MRIs performed for other reasons.


Several tests are used to diagnose pituitary tumors.


Surgery is the predominant treatment for pituitary adenomas. Treatment is important for functional or large tumors; however, small, asymptomatic nonfunctional adenomas (incidentalomas) are closely watched and not necessarily treated unless they grow.


Pituitary adenomas are not associated with any known lifestyle or environmental risk factors, so there are no available methods to prevent the condition. People with a family history of pituitary tumors associated with inherited genetic syndromes should be regularly monitored for early signs of the disorder.


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Tina Shahian, PhD

Tina is a writer for Innerbody Research, where she has written a large body of informative guides about health conditions.


A communication specialist in life science and biotech subjects, Tina’s successful career is rooted in her ability to convey complex scientific topics to diverse audiences. Tina earned her PhD in Biochemistry from the University of California, San Francisco and her BS degree in Cell Biology from U.C. Davis. Tina Shahian’s Linkedin profile.


In her spare time, Tina enjoys drawing science-related cartoons.