Doctors use many tests to diagnose a tumor and find out if it is cancerous and, if so, if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of tumors, a biopsy is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the cancerous tumor has metastasized. Your doctor may consider these factors when choosing a diagnostic test:
- Age and medical condition
- Type of tumor suspected
- Severity of symptoms
- Previous test results
In addition to a physical examination, the following tests may be used to diagnose an endocrine tumor:
Biopsy . A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is examined by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). There are many types of biopsies. The type of biopsy performed will depend on the location of the tumor. Two of the more common types of biopsies used in the diagnosis of an endocrine tumor include fine needle aspiration and surgical biopsy.
- Fine needle aspiration is usually performed in a doctor's office or clinic. A local anesthetic may be injected into the skin near the tumor beforehand to numb the area. The doctor inserts a thin needle into the tumor and removes cells and some fluid. The procedure may be repeated two or three times to get samples from different parts of the tumor. The report done by the pathologist can be positive (meaning there are cancerous cells), negative (meaning there are no cancerous cells), or undetermined (unclear).
- If the needle aspiration biopsy is undetermined, the doctor may suggest a biopsy in which the tumor and possibly other tissue in the area will be removed by surgery. This procedure is most often done under general anesthesia and on an outpatient basis.
Laboratory tests. The doctor may need samples of the patient's blood, urine, and stool to check for abnormal levels of hormones, glucose levels, and other substances.
Neurological examination. An evaluation of the central nervous system may include testing of the reflexes, motor and sensory skills, balance and coordination, and mental status.
Bone scan . A bone scan uses a radioactive tracer to look at the inside of the bones. The tracer is injected into a patient's vein. It collects in areas of the bone and is detected by a special camera. Healthy bone appears gray to the camera, and areas of injury, such as those caused by cancer, appear dark.
Computed tomography (CT or CAT) scan . A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient's vein to provide better detail.
Endoscopy . This test allows the doctor to see inside the body with a thin, lighted, flexible tube called an endoscope. The person may be sedated as the tube is inserted through the mouth, down the esophagus, and into the stomach and small bowel. A colonoscope  is a type of endoscope that is inserted through the anus into the colon. It can be used to diagnose a tumor in the lower section of the digestive system.
X-ray. An x-ray is a way to create a picture of the structures inside of your body, using a small amount of radiation.
Magnetic resonance imaging (MRI) . An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient's vein to create a clearer picture.
Positron emission tomography (PET) scan . A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a patient's body. This substance is absorbed mainly by organs and tissues that use the most energy. Because a tumor tends to use energy actively, it absorbs more of the radioactive substance. However, because some endocrine tumors grow very slowly, it means they use less energy; this means a PET scan may not be as helpful as other tests in the diagnosis.
Radionuclide scanning (OctreoScan). A small amount of a radioactive hormone-like substance is injected into a vein. A special camera is then used to show where the radioactivity accumulates. This procedure is useful for finding where an endocrine tumor has spread, especially if it has spread to the liver. The test takes place over more than one day.
Learn more about what to expect when having common tests, procedures, and scans .
After these diagnostic tests are done, your doctor will review all of the results with you. If the diagnosis is an endocrine tumor, these results also help the doctor describe the tumor; this is called staging . Learn more about the first steps to take after a diagnosis of a tumor .