What to know about an enlarged pituitary gland

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The pituitary gland is a small gland connecting to an area of the brain called the hypothalamus. Doctors also call the pituitary gland the hypophysis.

The pituitary gland works with the hypothalamus to release various hormones. These include:

• Thyroid stimulating hormone (TSH): TSH triggers the secretion of thyroid hormones and tells the thyroid how much thyroid hormone to produce. Thyroid hormones affect various bodily functions, such as muscle strength, mood, weight, and body temperature.
• Growth hormone: Growth hormone controls the growth of muscles, bones, and organs. Too much growth hormone can cause a person to be much taller than average height. Too little growth hormone can result in short stature.
• Prolactin: Prolactin causes tissue to develop in the breast during pregnancy. It helps stimulate breast milk production.
• Adrenocorticotropic hormone (ACTH): ACTH triggers cortisol secretion in the adrenal glands. Cortisol is a hormone that prepares the body to react to stressful or dangerous situations.
• Gonadotropic hormones: These hormones help regulate the growth and function of the testes and ovaries.

The pituitary gland is typically about 1 centimeter in diameter. Various conditions can cause it to become larger than usual.

An enlarged pituitary gland may disrupt normal hormone production, which can lead to complications such as:

• hypothyroidism (underactive thyroid)
• gigantism
• fertility problems

As the gland enlarges, it may also compress nearby structures in the brain, leading to complications such as vision loss.

Read about hormonal imbalances.

The symptoms of an enlarged pituitary gland may vary depending on the underlying condition causing its enlargement.

Symptoms may include:

• headaches
• nausea
• fatigue
• dizziness
• muscle weakness
• joint pain
• low or high blood pressure
• weight changes
• increase or loss of body hair
• dry skin
• facial numbness
• tremors
• heat or cold intolerance
• anxiety
• fertility problems
• irregular periods
• heart palpitations
• vision changes or loss

Causes of an enlarged pituitary gland include:

Pituitary tumors

Pituitary tumors are the most common cause of an enlarged pituitary gland.

Almost all pituitary tumors are pituitary adenomas, which are noncancerous. Although they are benign, pituitary adenomas may cause various health complications.

Most pituitary tumors are functional, which means they produce excessive hormones.

Hypophysitis

Hypophysitis is a rare condition in which the pituitary gland becomes inflamed. The condition is typically related to an autoimmune dysfunction or may arise due to another condition, such as an infection or tumor.

Hypothyroidism

Hypothyroidism refers to an underactive thyroid, which does not produce enough thyroid hormones. This can cause the pituitary gland to produce excessive hormones, which triggers the production of endocrine cells called thyrotrophs. The increase in cells, called pituitary hyperplasia, can cause pituitary gland enlargement.

Pregnancy

In a typical pregnancy, the pituitary gland’s volume increases by about 70%. This is because the gland produces more of the specific type of cell that releases the hormone prolactin. Pregnancy may also cause pituitary adenomas and enlarge existing adenomas.

Neurosarcoidosis

Neurosarcoidosis is a type of sarcoidosis, a chronic inflammatory disease. Neurosarcoidosis affects the nervous system. It most commonly causes inflammation in the pituitary gland, hypothalamus, and facial and cranial nerves.

Tuberculosis (TB)

TB typically affects the lungs but may affect the pituitary gland in rare cases. Because primary pituitary TB occurs rarely, doctors may misdiagnose the condition as pituitary adenoma.

Medications

Some medications and hormone therapies may cause pituitary hyperplasia, which enlarges the pituitary gland. These include:

• estrogen
• gonadotropin releasing hormone (GnRH) agonists, such as leuprolide acetate (Lupron Depot)
• atypical antipsychotic medications

Read about pituitary gland disorders.

Doctors may perform various tests and assessments to diagnose an enlarged pituitary gland. These include:

• physical examinations
• tests for hormone levels in urine, blood, and saliva
• imaging scans, such as MRI
• vision tests

The treatment for an enlarged pituitary gland depends on the cause of the condition.

For pituitary adenomas, surgery to remove the tumor is typically the main treatment.

For hypothyroidism, a doctor may prescribe thyroid hormone replacement medications.

For other causes, a doctor may prescribe corticosteroids or medications to suppress a person’s immune response and reduce inflammation.

Below are answers to some frequently asked questions about enlarged pituitary glands.

Can an enlarged pituitary gland cause seizures?

It is possible, although uncommon, for an enlarged pituitary gland to cause seizures.

Seizures in people with an enlarged pituitary gland are usually due to other causes, such as electrolyte disturbances.

Is an enlarged pituitary gland a brain tumor?

In many cases, a noncancerous tumor called a pituitary adenoma causes an enlarged pituitary gland. The tumor is technically not a brain tumor because it is located at the base of the skull, below the brain.

The outlook for an enlarged pituitary gland depends on the cause of the condition.

The outlook for a person with a pituitary adenoma that does not produce hormones is generally positive with treatment such as surgery.

Functional pituitary adenomas that cause excessive hormone production can lead to conditions such as Cushing disease. These types of adenomas can lead to several complications. People may have a poorer outlook, especially when there are delays in treatment.

For other causes such as hypothyroidism, TB, and hypophysitis, treatment with medication or surgery can help relieve or cure the condition.

A noncancerous tumor called pituitary adenoma is the most common cause of an enlarged pituitary gland.

There are several other potential causes for an enlarged pituitary gland. These include conditions such as hypothyroidism, TB, and neurosarcoidosis. The pituitary gland can also enlarge during pregnancy.

The treatment for an enlarged pituitary gland depends on the cause of the condition and can involve surgery or medication, such as corticosteroids.