Soft Tissue Sarcoma: Diagnosis

If your healthcare provider thinks you might have a soft tissue sarcoma, you’ll need certain exams and tests to be sure. Diagnosing sarcoma 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. Your healthcare provider will also give you a physical exam.

What tests might I need?

You may have one or more of the following tests:

  • Imaging tests

  • Biopsy

Imaging tests

If you have a lump or other symptoms that might be caused by a soft tissue sarcoma, your healthcare provider may do imaging tests. If you’ve already been diagnosed with a soft tissue sarcoma, your healthcare provider may do imaging tests to see if the cancer has spread to other parts of the body. You may have one or more of these tests:

  • X-rays. You may have an X-ray of the lump first. If sarcoma is found, you may need a chest X-ray to look for spread to your lungs. 

  • Ultrasound. This test can sometimes see whether a tumor is a cyst (a fluid-filled sac that is probably not cancer) or a solid mass that is more likely to be cancer. An ultrasound uses sound waves to look for abnormalities. The sound waves bounce off body parts and send back a series of signals. Then a computer turns into images of your body.

  • Magnetic resonance imaging (MRI). This test uses magnets and radio waves to take detailed pictures of the inside of your body. An MRI can show details about the tumor, as well as look for cancer spread to other parts of the body.

  • Computed tomography (CT) scan. A CT scan uses X-rays taken from many angles to make very detailed cross-section pictures of tumors and other structures in your body. Like MRI, it can be used to look at a tumor or to look for cancer spread.

  • Positron emission tomography (PET). For this test, a small amount of radioactive sugar is injected into your blood. Cancer cells take up more of the sugar than normal cells. This can then be detected with a special camera. This test is not always needed for sarcomas. But when it’s done, it’s often done with a CT scan. 


If your healthcare provider thinks you might have a sarcoma, he or she may want to get small samples of the tumor. This is called a biopsy. Biopsies for suspected sarcomas must be done by healthcare providers with experience treating these tumors. Some ways to get a biopsy include the following:

  • Needle biopsy. For this test, a healthcare provider puts a thin, hollow needle through your skin and into the tumor to get a sample of it. If the tumor is deep in your body, this is often done during a CT or ultrasound. This lets your healthcare provider see the needle going into the tumor. 

  • Surgical biopsy. You may have a biopsy during surgery. If the tumor is small and easily accessible, your healthcare provider may take out the whole tumor. This is called an excisional biopsy. If the tumor is larger or would be harder to fully remove, your healthcare provider will only take out a small piece of it. This is called an incisional biopsy.

A doctor who specializes in looking at cells, called a pathologist, then looks at the samples under a microscope. He or she will tell whether it’s cancer. You may need other lab tests on the samples to see what type of cancer it is.

Getting your test results

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