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. You'll be asked about your health history, the symptoms you've been having, risk factors, and your family history of disease.
If your healthcare provider thinks you may have a pituitary tumor, you'll have a full medical evaluation. This includes a complete physical exam, blood and urine tests, and vision testing. These exams will help your healthcare provider decide if you need more tests.
What tests might I need?
If a pituitary tumor is suspected, you will need these tests to be sure:
Blood or urine tests
The kind of tests done will depend on what the healthcare provider finds during your physical exam. Certain tests can measure the levels of different hormones in your urine or blood. This helps your healthcare provider figure out what kind of pituitary hormone you might have. Different kinds of blood tests may be done depending on what kind of pituitary tumor your healthcare provider thinks you have. Some blood tests may need to be done at certain times of the day. Urine may need to be collected in a large container over a 24-hour period.
A special test called venous blood sampling may be done to see if you have a certain kind of tumor. Pituitary tumors that make the hormone ACTH (corticotropin) may be too small to show up on a magnetic resonance imaging (MRI) scan. If you have a high ACTH level, but your MRI scan is normal, a venous blood sampling test may be done. To do this, tiny tubes are put into veins inside each of your thighs. The tubes are guided up to the veins that drain blood on each side of your pituitary gland. Blood samples are taken from both sides and checked for hormone levels. Then a hormone that causes the pituitary to make ACTH is put into your blood. More blood samples are taken to see if your ACTH level goes up a lot or is higher on one side of your pituitary gland. If this happens, a pituitary tumor is likely the cause.
MRI uses magnets and radio waves to take pictures of the inside of your body. MRI scans can show more detail than other imaging tests. An MRI is the best imaging test to find all types of pituitary tumors. MRI scans can also help surgeons decide on the type of surgery to use to remove the tumor, if needed.
A dye might be put into your blood or taken as a pill before an MRI scan. It helps make the pictures of your brain clearer so that even small changes can be seen.
During the test, you lie still on a table as it passes into a long, narrow scanner tube. If you're uncomfortable in small spaces (claustrophobic), you may need medicine (a sedative) to help you relax before the test. The entire test may last an hour or more, but each image takes only a few minutes. You will need to be very still while the images are taken. An MRI scan doesn't hurt, but it is noisy. You can ask for earphones and music or ask for earplugs.
A CT scan is a machine that takes many X-rays as the camera moves around you. A computer combines these images to create detailed pictures of the inside of your body. This test may be done if you can't have an MRI scan.
During the test, you lie on a table as it slides into the ring-shaped scanner. A CT scan is painless. But you'll need to be still and may be asked to briefly hold your breath a few times during the scan.
You may have a contrast dye put into one of your veins as part of this test. The dye helps your provider see certain parts of your body more clearly. The dye will pass through your body and come out through your bowel movements. When the dye is injected, you may have a warm feeling flush from your chest to your groin. Before you get a CT scan, be sure to tell your provider about any allergies or if you've ever had a reaction to contrast dye. This includes hives, trouble breathing, or suddenly feeling hot. Medicines can be given before the test to help prevent these kinds of reactions.
Pituitary tissue biopsy
A biopsy is when a tiny piece of tissue or tumor (a sample) is removed and checked under a microscope. This can help your healthcare provider figure out the exact kind of pituitary tumor you have, and if it's cancer. But a biopsy is seldom needed before treating a pituitary tumor. This is because high-resolution MRI scans and detailed hormone blood 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 test results and what you need to do next.