Pheochromocytoma and Paraganglioma: Diagnosis

Approved by the Cancer.Net Editorial Board, 12/2018

ON THIS PAGE: You will find a list of common tests, procedures, and scans that doctors use to find the cause of a medical problem. Use the menu to see other pages.

Doctors use many tests to find, or diagnose, a pheochromocytoma or paraganglioma. They also do tests to learn if cancer has spread to another part of the body from where it started. If this happens, it is called metastasis. For example, imaging tests can show if the cancer has spread. Imaging tests show pictures of the inside of the body. Doctors may also do tests to learn which treatments could work best.

Some pheochromocytomas and paragangliomas are found unexpectedly when people have tests and procedures for reasons unrelated to the tumor, if a lump forms on the neck, or if the tumor presses on other organs and causes symptoms.

For most types of cancer, a biopsy is the only sure way for the doctor to know whether an area of the body has a tumor. In a biopsy, the doctor takes a small sample of tissue for testing in a laboratory. However, tumors suspected to be a pheochromocytoma or paraganglioma should not have a biopsy, unless it is absolutely necessary to confirm a diagnosis. A biopsy of these tumors can cause a serious and even life-threatening release of catecholamines. In addition, it can be difficult to tell if these tumors are benign or malignant under a microscope, even after surgically removing the tumor (learn more about treatments in Types of Treatment). The only sure way to know if a pheochromocytoma or paraganglioma is malignant is if it has metastasized or if it comes back, called a recurrence.

This list describes options for diagnosing pheochromocytomas and paragangliomas. Not all tests listed below will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • The type of tumor suspected

  • Your signs and symptoms

  • Your age and general health

  • The results of earlier medical tests

If a doctor suspects a pheochromocytoma or paraganglioma, he or she will ask for a complete medical and family history and perform a physical examination. In addition, the following tests may be used to diagnose these tumors:

  • Blood/urine tests. The doctor may collect blood and urine samples to check for abnormal levels of catecholamines and other substances. If these biochemical tests indicate a pheochromocytoma or paraganglioma, imaging tests (described below) are used to confirm the diagnosis and determine the location and size of the tumor. This is called localization.

    Urine tests check for increased levels of catecholamines in the body as well as metanephrines. When catecholamines break down, they turn into metanephrines. Large amounts can be a sign of a pheochromocytoma or a paraganglioma. These tests require a person to collect all of his or her urine for an entire 24-hour period.

    The glucagon stimulation test and clonidine (Catapres) suppression test are blood tests that measure adrenaline levels for people who sometimes have symptoms of a pheochromocytoma or paraganglioma. During the glucagon stimulation test, glucagon is injected into a vein. Glucagon is a hormone produced by the pancreas that helps the body process carbohydrates. Blood samples are then drawn at specific times to measure adrenaline levels.

    During the clonidine suppression test, a tablet of the drug clonidine is swallowed, and blood samples are taken on a regular schedule over the next 3 hours. Clonidine is used to lower adrenaline levels in the blood, so if these levels do not decrease during testing, it may be a sign of a pheochromocytoma or paraganglioma. Blood pressure and heart rate are also carefully monitored during these tests.

  • X-ray. An x-ray is a way to create a picture of the structures inside of the body, using a small amount of radiation.

  • Computed tomography (CT or CAT) scan. A CT scan takes pictures of the inside of the body using x-rays taken from different angles. A computer combines these images into a detailed, 3-dimensional image that shows any abnormalities or tumor. A CT scan can be used to measure the tumor’s size. Sometimes, a special dye called a contrast medium is given before the scan to provide better detail on the image. This dye can be injected into a patient’s vein or given as a pill or liquid to swallow.

  • Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. MRI can be used to measure the tumor’s size. A special dye called a contrast medium is given before the scan to create a clearer picture. This dye can be injected into a patient’s vein or given as a pill or liquid to swallow.

  • Genetic testing. Your doctor may recommend testing your blood for certain gene mutations associated with pheochromocytomas and paragangliomas. If a gene mutation is found, genetic counseling may be recommended.

  • Nuclear medicine imaging. During this test, a small amount of a radioactive drug, called a tracer, is injected into a patient’s vein. The body is then scanned to show where the radioactivity has built up in the body. There are different methods of nuclear medicine imaging for NETs, including OctreoScan and 2 types of PET-CT scans.

    • OctreoScan. This imaging test uses octreotide linked with indium-111 as the tracer. This procedure is useful for identifying where a NET has spread, especially if it has spread to the liver. OctreoScan is slowly being replaced by the newer and more sensitive gallium-68 DOTATATE PET scan (see below).

    • Positron emission tomography (PET) or PET-CT scan.  A PET scan is usually combined with a CT scan (see above), called a PET or PET-CT scan. The 2 types of tracers used in a PET scan include gallium-68 (68Ga) DOTATATE and (18F) fluorodeoxyglucose (FDG). The 68Ga DOTATATE PET is the primary scan used to look at slow-growing NETs. An FDG PET scan is sometimes used for faster-growing NETs. 

    • Metaiodobenzylguanidine (MIBG) scan. MIBG is a chemical similar to adrenaline that will collect in a pheochromocytoma or paraganglioma. The MIBG scan takes place over 2 consecutive days. On the first day, an injection of MIBG is given in the arm. Several hours later, pictures are taken with a special camera that can show if or where in the body the MIBG has collected. The following morning, more pictures are taken, and the process may be repeated if needed. This scan may be used when a CT scan or MRI does not show a tumor that biochemical tests indicate is present.

After diagnostic tests are done, your doctor will review all of the results with you. If the diagnosis is cancer, these results also help the doctor describe the tumor. This is called staging.

The next section in this guide is Stages. It explains the system doctors use to describe the extent of the disease. Use the menu to choose a different section to read in this guide.