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Pituitary Tumor: Diagnosis

How are pituitary tumors diagnosed?

If your healthcare provider thinks you might have a pituitary tumor, you will need certain exams and tests to be sure. Diagnosing pituitary tumors starts with your healthcare provider asking you questions. He or she will ask you about your health history, your symptoms, risk factors, and family history of disease.

If your doctor thinks you may have a pituitary tumor, you will have a full medical evaluation. This includes a complete physical exam and vision testing. These exams will help your doctor decide if you need more tests.

lab technician drawing blood from a person's arm
Blood testing may be done to measure the levels of certain hormones.

What tests might I need?

If a pituitary tumor is suspected, you may have several tests. These include:

  • Blood tests

  • Urine tests

  • Imaging tests

  • Biopsy

Blood or urine tests

The kind of tests you have will depend on what the doctor finds in your physical exam. The doctor will measure a set of hormone levels in your urine or blood. Different kinds of blood tests may be done depending on what kind of pituitary tumor you are believed to have. Blood tests may be done at certain times of the day. Urine may need to be collected in a large container over a 24-hour period. 

A venous blood sampling test may be done to see if you have a certain kind of tumor. Pituitary tumors that send out the hormone ACTH (corticotropin) may be too small to show up on an MRI. If you have a high ACTH level but your MRI scan is normal, a venous blood sampling test may be done. Small tubes are guided into the veins that drain blood on each side of the pituitary gland. Blood samples are taken from both sides and checked for hormone levels.

Imaging tests

MRI uses magnets and radio waves to take pictures of the inside of the body. MRIs can show more detail than other imaging tests. The MRI is the standard imaging test used to find pituitary tumors of all types. MRIs can also help surgeons to select the type of surgery to remove the tumor, if needed.

During the test, you lie still on a table as it passes into a long, narrow scanner tube. The tube is a small space. If you are uncomfortable in small spaces (claustrophobic), you may be given medicine (a sedative). This will relax you before the test. The scanner takes 2 to 15 minutes to make an image. You may need more than 1 set of images. The test may last an hour or more. An MRI test is painless, but it is noisy. You can bring earphones and an MP3 device, or ask for earplugs.

A CT scan is a ring-shaped machine that takes many X-rays as it moves around you. A computer combines these images to create detailed pictures that your doctor can view. During the test, you lie still on a table as it slides into a CT scanner. A CT scan is painless. You may be asked to hold your breath 1 or more times during the scan.

You may have a contrast dye injected into a vein. The dye helps your provider to see certain parts of the body more clearly. The dye will pass through your body and exit through your bowel movements. When the dye is injected, you may have a warm feeling from your chest to your groin. Tell your healthcare provider if you have ever had a reaction to contrast dye. This includes hives, trouble breathing, or suddenly feeling hot. Special medicines can be given before the test to help prevent these kinds of reactions.

Pituitary tissue biopsy

A biopsy is when a tissue or tumor sample is removed and checked under a microscope. This can help your doctor figure out the exact kind of pituitary tumor you have, and if it is cancer. But a biopsy is often not needed before treating a pituitary tumor. That’s because high-resolution MRI images and detailed hormonal tests are very accurate. 

Getting your test results

When your healthcare provider has the results of your tests or biopsy, he or she will contact you. Your provider will talk with you about other tests you may need if a pituitary tumor is found. Make sure you understand the results and what follow-up you need.

Online Medical Reviewer: Gersten, Todd, MD
Online Medical Reviewer: Stump-Sutliff, Kim, RN, MSN, AOCNS
Date Last Reviewed: 5/1/2016
© 2013 The StayWell Company, LLC. 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare provider's instructions.
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