What Can Cause an Enlarged Pituitary Gland?
An enlarged pituitary gland doesn’t necessarily mean you have a tumor. It could be a sign of another condition or an immune reaction. The pituitary gland even enlarges naturally during pregnancy.
Your pituitary gland is a small, pea-sized gland located just behind your nose on the base of your brain. Though small, it serves many important purposes related to hormone secretion.
An enlarged pituitary gland can be problematic because there’s only so much room in your skull. When the pituitary gland gets bigger, it can press on surrounding brain structures, resulting in various potential symptoms.
The most common reason for an enlarged pituitary gland is a tumor. Most of these tumors are benign (noncancerous), but some may be malignant (cancerous).
But a tumor isn’t the only possible explanation for an enlarged pituitary gland. Keep reading to learn about some of the potential nontumor causes.
What are the symptoms of an enlarged pituitary gland?
An enlarged pituitary gland can cause various symptoms, including:
- depression
- fatigue
- headaches
- infertility
- joint pain
- muscle weakness
- nausea
- problems seeing, like blurred or double vision
- problems with smell and taste
- production of breast milk not related to childbirth or pregnancy
- vomiting
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Hypothyroidism is when your thyroid gland doesn’t produce enough hormones. Your pituitary gland starts to overproduce hormones because it doesn’t get feedback from the thyroid gland. This causes pituitary hyperplasia (an increase in the number of cells), resulting in an enlarged pituitary gland.
In these cases, healthcare professionals treat pituitary hyperplasia by prescribing thyroid hormone replacement medications. Treatments may take 2 to 4 months before the pituitary gland starts to get smaller. In rare cases, a person may need surgery to prevent permanent vision loss.
Pregnancy naturally enlarges the pituitary gland through hyperplasia, sometimes by as much as 70% . The pituitary gland produces prolactin, a hormone responsible for breast enlargement and milk production in pregnancy and post-delivery.
Pregnancy can also cause a pituitary adenoma, or noncancerous growth, to enlarge. As a result, a pregnant person may experience symptoms that include vision difficulties and headaches.
Treatments for pregnancy-related symptoms from an enlarged pituitary gland depend upon the birthing parent’s symptoms and how far along they are in their pregnancy. In severe instances of visual problems, a doctor may recommend early delivery when a doctor can safely induce labor or perform a Cesarean section.
A healthcare professional will often monitor the pregnant person to determine if the pituitary gland shrinks or may require surgery.
Some medications or hormone therapies may also cause pituitary hyperplasia, including :
- atypical (second-generation) antipsychotics
- GnRH antagonists
- estrogen
Some people assigned male at birth receive estrogen therapy as part of gender-affirming care. While some reports suggest a link between estrogen therapy and the development of pituitary tumors in this population, a 2020 review notes that research has yielded mixed results.
Tuberculosis (TB) is a rare cause of an enlarged pituitary gland. While TB is usually a respiratory-related condition, the TB bacteria can infect other areas, including your pituitary gland.
Treatments for TB-related pituitary enlargement include anti-TB medications. If your pituitary gland becomes very enlarged, a surgeon may perform surgery to decompress where the pituitary gland is pressing.
Sarcoidosis is an inflammatory disorder that most commonly affects your lungs. But it can also cause inflammation in your nervous system, including the pituitary gland. When the condition occurs in nervous system tissue, like the pituitary gland, healthcare professionals call it neurosarcoidosis.
Neurosarcoidosis can be difficult to diagnose because the condition is rare and progresses unpredictably. While there’s no cure for the condition, doctors may prescribe steroids to reduce inflammation and suppress the immune system.
The prognosis for neurosarcoidosis affecting your pituitary gland can depend on your overall symptoms and response to treatment.
Hypophysitis is inflammation of the pituitary gland that causes it to be enlarged. The underlying cause is usually an autoimmune, infectious, or other disorder. Sometimes, a healthcare professional may not be able to identify the underlying cause of hypophysitis.
Treatments for hypophysitis usually depend on the underlying cause. Taking oral steroids can often help relieve inflammation. Other treatments may include other immunosuppressive drugs, like azathioprine, methotrexate, or rituximab.
A healthcare professional will usually order one or more tests to determine if you have an enlarged pituitary gland. These tests include:
- Hormone testing: A blood or urine test may help determine if there are irregular levels of hormones produced by your pituitary gland.
- Imaging:Magnetic resonance imaging (MRI) uses a magnet to generate images of the brain’s structure to help determine if your pituitary gland is enlarged.
- Vision exam: Your doctor may perform a vision exam to determine what parts of your vision are affected.
An MRI is the most effective method to determine if you have an enlarged pituitary gland.
An enlarged pituitary gland can be the result of various medical conditions. Some are due to inflammatory or immune system processes.
If you have symptoms of an enlarged pituitary gland, talk with a doctor about testing. Treatments are available for most enlarged pituitary gland-related conditions.
Last medically reviewed on March 9, 2023