Pheochromocytoma and Paraganglioma: Diagnosis

Approved by the Cancer.Net Editorial Board, 11/2022

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 the cancer has spread, 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, a tumor 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 after treatment, called a recurrence.

How a pheochromocytoma or paraganglioma is diagnosed

There are different tests used for diagnosing pheochromocytomas and paragangliomas. Not all tests described here 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, they 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 their urine for an entire 24-hour period.

  • X-ray. An x-ray creates 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 pictures 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 produces detailed images of the inside of the body using magnetic fields, not x-rays. 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. Genetic testing and genetic counseling are recommended for all people with a paraganglioma or pheochromocytoma. Your blood or saliva will be tested for certain gene mutations associated with these tumors.

  • 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. However, the amount of radiation in the substance is too low to be harmful. There are different methods of nuclear medicine imaging for neuroendocrine tumors (NETs):

    • 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 tracer used in a PET scan may include gallium-68 (68Ga) DOTATATE, copper-64 (64Cu) DOTATATE, (18F) fluorodeoxyglucose (FDG), and 18F FDOPA. The DOTATATE PET is the primary scan used to look at slow-growing NETs. An FDG PET scan is sometimes used for faster-growing NETs. The DOTATATE PET scan has replaced a different method of nuclear imaging called OctreoScan because it is more effective. A 64Cu DOTATATE PET scan is the latest tracer to be made available to locate 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 days in a row. 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 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.