Nonfunctioning Pituitary Adenoma

Dr. Elena Varlamov, neuroendocrinologist, reviews brain scans with a colleague
Dr. Elena Varlamov, neuroendocrinologist, reviews brain scans with a colleague.

Nonfunctioning pituitary adenomas do not produce hormones, but they can disrupt hormone production. They can also cause problems by pressing on the pituitary gland or an optic nerve. Patients from across the U.S. turn to the OHSU Pituitary Center for our expertise because:

  • Our skilled neurosurgeons do more than 100 tumor surgeries in and around the pituitary gland every year. This large number leads to better patient outcomes.
  • We use minimally invasive procedures whenever possible, resulting in a precise surgery and an easier recovery.
  • Our specialists offer the experience to pinpoint even hard-to-diagnosis pituitary conditions.
  • Our patients have access to many clinical trials testing the latest treatments.

Learn more about:

Understanding nonfunctioning pituitary adenomas

What is a nonfunctioning pituitary adenoma?

A pituitary adenoma is a noncancerous, slow-growing tumor that affects the pituitary gland, a pea-size structure at the base of the brain that controls hormone production.

About 40 percent of pituitary adenomas are nonfunctioning. That means they don’t cause the body to make extra hormones. They may still cause health problems, though, if they become large enough to press on parts of the brain. Scientists don’t know what causes these tumors.

Who gets a nonfunctioning pituitary adenoma?

Nonfunctioning pituitary adenomas are relatively common. Often, doctors find these tumors during scans for other conditions. The tumors mostly occur in adults in their 40s through 80s.

Symptoms and complications of nonfunctioning pituitary adenomas

Symptoms vary depending on the size and location of the tumor. They may include:

  • Headaches, caused by:
    • The tumor stretching the covering of the brain, called the meninges.
    • The center of a large tumor dying, which can cause sudden, intense headaches.
  • Vision loss if the tumor presses on the area where nerve fibers carry information from your peripheral (side) vision.
  • Difficulty aiming your eyes in the right direction, caused by the tumor pressing on a nerve in the brain near your eye.
  • Fatigue and weakness.

As the tumor grows, it can damage normal pituitary tissue, causing the pituitary gland to produce fewer hormones. If the tumor damages the pituitary gland, you may need to take extra hormones in pill form, even after surgery to remove the tumor.

Types of nonfunctioning pituitary adenomas

Doctors sometimes classify adenomas by their size:

Microadenomas: These are tiny tumors, about 2 to 3 millimeters across, or the size of a peppercorn. About 10% of patients with a pituitary adenoma have this type. Many don’t know they have one because they rarely cause symptoms.

Macroadenomas: These adenomas are larger than 1 centimeter across, or about the size of a pea. This type can cause symptoms as it grows.

Diagnosing nonfunctioning pituitary adenomas

Nonfunctioning pituitary adenomas can be challenging to diagnose. The symptoms are similar to those of other conditions. At the OHSU Pituitary Center, you’ll find specialists with the expertise to give you a precise diagnosis and tailored-to-you treatment plan.

Exam: We begin by doing a physical examination and asking you about your symptoms.

Blood tests: Specialized blood tests help us see if the pituitary gland is making too much or too little prolactin, growth hormone (GH), adrenocorticotropic hormone (ACTH) or other hormones. Blood tests can also reveal other problems caused by pituitary changes.

Pregnancy test: We may ask women of childbearing age to take a pregnancy test to rule out pregnancy as a source of hormone production.

Cosyntropin/ACTH stimulation tests: This test measures ACTH and cortisol levels. We take a blood sample before giving you a dose of ACTH through an IV in your arm. We then take one or more blood samples to measure the rise of cortisol levels in your blood.

Imaging: MRI scans can help us see the size and location of a tumor and whether it’s affecting your eyesight. If you’ve already had an MRI, we’ll repeat it only if your first scan doesn’t show enough detail.

Neuro-ophthalmologist evaluation: We may recommend that you see a neuro-ophthalmologist, a specialist in vision problems related to the nervous system. The specialist will test your vision to see if the tumor is affecting an optic nerve.

Nonfunctioning pituitary adenoma treatments

The main treatment for nonfunctioning pituitary adenomas is surgery. You may need radiation therapy after surgery. After your treatment, we provide follow-up care. Most patients have hormonal testing and an MRI each year for at least five years.

Patients who have treatment often have good results, with:

  • Symptom improvement: Surgery generally improves vision problems and headaches.
  • Regained function: In some patients, the pituitary gland starts to work normally again.
  • Low rate of recurrence: If a neurosurgeon removes the tumor, it usually doesn’t return. Tumors do come back in 20-30% of patients.


Our neurosurgeons use a minimally invasive procedure called transsphenoidal surgery to remove the tumor through the nose. This method leaves no visible scarring, avoids delicate structures in the brain and speeds recovery. We use tiny surgical tools with either an endoscope — a lighted scope with a camera — or a microscope to magnify the surgical area.

Our surgeons do more than 100 tumor surgeries in and around the pituitary gland each year. That experience means they have great skill with these procedures.

Radiation therapy

If we can’t completely remove the tumor, we will sometimes recommend radiation therapy. This treatment helps shrink the tumor or prevent it from growing.

At the OHSU Pituitary Center, we use the Novalis Tx radiosurgery system, the most advanced radiation therapy equipment available. We meticulously plan the radiation therapy, molding the beams to the shape of the tumor and sparing healthy tissue.

Learn more

For patients

  • Referral: To become a patient, please ask your doctor for a referral.
  • Questions: For questions or follow-up appointments, call 503-494-4314.


Parking is free for patients and their visitors.

OHSU Pituitary Center
Center for Health & Healing Building 1
3303 S. Bond Ave.
Portland, OR 97239
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