Dr. Maria Fleseriu is one of the world’s leading experts on acromegaly. Her extensive research has led to new medications and other treatment improvements.
Dr. Maria Fleseriu is one of the world’s leading experts on acromegaly. Her extensive research has led to a new medication and other treatment improvements.

People across the United States turn to the OHSU Pituitary Center for expert acromegaly treatment.

  • Dr. Maria Fleseriu, OHSU Pituitary Center director, is an international expert in acromegaly and other pituitary disorders.
  • We treat more than 250 patients with acromegaly at a time, a high number for this rare disease.
  • We stress both medical success and your well-being in our treatment, based on our own research.
  • We typically complete all your testing in one day.
  • Our highly skilled neurosurgeons use minimally invasive methods to remove tumors.
  • Our work in clinical trials helped lead to FDA approval for a new acromegaly medication.

Learn more about:

Understanding acromegaly

What is acromegaly?

Acromegaly occurs when the pituitary gland (a pea-size gland at the base of the brain) makes too much growth hormone (GH). Excess GH causes bones and organs to grow too large. Acromegaly gradually worsens over time. Without treatment, acromegaly can lead to complications, including life-threatening heart and blood vessel disease.

Treatment can reduce the risk of complications as well as improve symptoms and quality of life. Treatment that returns GH levels to normal gives patients a regular life expectancy.

Who gets acromegaly?

Incidence: Acromegaly is rare, affecting an estimated 50-70 people per million, with about three in 1 million people diagnosed each year. These figures may undercount the true number, however, as other people with acromegaly may be going undiagnosed.

Age: Acromegaly is found most often in middle-age adults. Though acromegaly can begin any time after puberty, it develops slowly, so patients are often in their 40s or 50s when diagnosed.

Sex: Men and women are at equal risk.

What causes acromegaly?

In about 95% of cases, a noncancerous (benign) pituitary tumor called an adenoma causes the pituitary gland to make too much GH.

GH, in turn, causes the liver to make too much of a hormone called insulin-like growth factor-1 (IGF-1). This hormone signals bones and other tissues to grow. In rare cases, a tumor in another part of the body causes acromegaly.

In most cases, doctors don’t know what causes these slow-growing tumors to form. Acromegaly and pituitary adenomas are not passed down in families.

Symptoms and complications of acromegaly

Acromegaly can take years to develop. Changes can be so subtle that by the time you are diagnosed, you may have had the condition for some time. Often, people seek care for headaches or vision problems that arise as the tumor grows.

Symptoms include:

  • Hands and feet getting larger (you may notice your ring or shoe size increasing over 10 to 15 years)
  • Jaw and forehead getting larger
  • Painful, swollen (arthritic) joints and back pain
  • Thickened skin and skin tags
  • Oily skin
  • Increased sweat
  • Deepening voice

People with acromegaly often develop other medical conditions, such as:

  • Carpal tunnel syndrome (stiffness and pain in the wrist that can cause finger numbness)
  • High blood pressure
  • Heart and blood vessel disease
  • High blood sugar or diabetes
  • Noncancerous growths, or polyps, in the colon
  • Sleep apnea (interrupted breathing while you sleep)
  • Vision problems

Diagnosing acromegaly

Acromegaly can be challenging to diagnose. People turn to OHSU for our expert diagnosis and experience with this condition. We know you want quick answers, so we often complete your tests and appointment in one day.

Tests may include:

  • Blood test: We take a blood sample to check your levels of growth hormone and IGF-1. High levels of both may suggest acromegaly. You may need more tests for a firm diagnosis.
  • GH suppression test: After you fast overnight, we give you a sugary drink and then take blood samples over two hours. We measure your blood sugar, GH and IGF-1 each time. If GH is high, it may be a sign of acromegaly.
  • Imaging: We take an MRI to see the size and location of any unusual pituitary growth. Imaging can also show if a tumor is affecting your vision.
  • Vision testing: A neuro-ophthalmologist, a specialist in the connection between the brain and optic nerves, may check your vision.

Types of acromegaly

  • Controlled acromegaly is when treatment keeps GH and IGF-1 within normal levels.
  • Active acromegaly is when someone has symptoms. The tumor may be too large to remove, or medication may not control GH and IGF-1.

Acromegaly treatments

Surgery to remove the tumor is often the first step. You also may need medication and radiation therapy. Your care team will work with you to develop a treatment plan that best meets your needs.

We’ll make sure to focus on your quality of life, based on our pioneering research. We’ll check how medications are affecting you, for example. This approach is now an accepted best practice.

Long-term monitoring is also important. The hormonal imbalance caused by acromegaly can put you at risk for heart problems, colon growths and other conditions.


In addition to producing too much GH, tumors can press on the pituitary gland or an optic nerve. This can affect your vision, cause headaches or affect hormone production. It can lead to symptoms such as weight gain and sexual problems. If your surgeon can remove the tumor completely, you may not need any other treatments.

Expertise: Our neurosurgeons remove more than 100 tumors in and around the pituitary gland each year. As a result, we have a high level of skill and experience. Studies show that high volume of cases leads to better results for patients.

Minimally invasive surgery: We often use a minimally invasive technique called transsphenoidal surgery to remove the tumor through the nose. This precise approach leaves no noticeable scars and has fewer side effects and risks. Most patients go home two days after surgery.


You may need medication if you:

  • Can’t have surgery because of other health reasons.
  • Had surgery, but your neurosurgeon couldn’t remove the entire tumor because of its size or location.
  • Have excess GH, but doctors can’t see the tumor on scans to chart its size and location.

We will work with you to find the right medication and dose, and to manage any side effects.

Expertise: We played a central role in designing and running clinical studies that resulted in FDA approval for pasireotide and mifepristone, medications for acromegaly and Cushing disease.

Medications may include:

  • Somatostatin receptor ligands: These medications, often given in a monthly injection, mimic the brain hormone somatostatin to stop too much GH production. They can also shrink a pituitary tumor in some patients.
  • Growth hormone receptor antagonists: These medications block the effects of GH. Doctors may recommend them if other treatments didn’t help. Your doctor will teach you how to give yourself daily injections. The medications often return IGF-1 levels to a normal range, improving symptoms. They do not affect GH levels or the size of the tumor.
  • Dopamine agonists: Taken as pills, these medications may lower the levels of GH and IGF-1. They may also shrink the tumor.

Radiation therapy

Some patients have an aggressive type of acromegaly, with high GH levels persisting after treatment. In these cases, we may recommend radiation therapy. Depending on your needs, you may have traditional radiation therapy or a type called stereotactic radiosurgery.

Precise procedure: We use the most advanced equipment available for stereotactic radiosurgery. The Novalis Tx radiosurgery system provides a detailed view of the tumor. It enables our team to deliver targeted radiation beams to the tumor while protecting healthy tissue. Patients typically have a series of treatments, with small doses over four to six weeks.

Combined treatment: Radiation treatment is usually followed by medication to slow tumor growth and to control GH levels. It can take up to two years to start seeing results on a slow-growing tumor. The entire treatment process can take up to 10 years.

Clinical trials

We are part of the OHSU Brain Institute, a national leader in offering clinical trials to test new treatment approaches. Your care team will talk with you about any trial that is right for you.

Support group

Ask your care team about our acromegaly support group, led by a nurse on our team.

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
Map and directions

Back in the garden

Learn how our team at OHSU discovered and treated Jim Pritchard’s acromegaly.