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. You'll be asked about your health history, your symptoms, risk factors, and your family's medical history. Your healthcare provider will also do a physical exam.

What tests might I need?

You may have 1 or more of these tests:

  • Imaging tests

  • Biopsy

Imaging tests

If you have a lump (tumor) or other symptoms that might be caused by a soft tissue sarcoma, your healthcare provider may do imaging tests. The type of test done often depends on where the lump is. You may get 1 or more of these tests:

  • X-rays. An X-ray of the lump is often the first test done.

  • Ultrasound. This test can sometimes show if a lump is a cyst (a fluid-filled sac that's probably not cancer) or a solid mass that's more likely to be cancer. An ultrasound uses sound waves to look for tissue changes. The sound waves come from a wand that's moved over your skin around the area with the tumor. They bounce off body parts and send back a series of signals. A computer turns these signals into images of the inside of your body.

  • MRI. This test uses magnets and radio waves (not X-rays) to take detailed pictures of the inside of your body. An MRI scan can show details about the lump, such as its size, the kind of tissue it started in, and whether it has spread to nearby tissues.

  • CT scan. A CT scan uses X-rays taken from many angles to make very detailed cross-section pictures of the lump and other structures in your body. Like MRI, it can be used to learn details about the lump. A CT scan might be used to help guide the needle for a biopsy. (See below.)

  • Positron emission tomography (PET).  For this test, a small amount of radioactive sugar is put right 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 isn't always needed for sarcomas. And when it’s done, it’s usually done with a CT scan. 


If imaging tests suggest you might have a sarcoma, tiny pieces of the tumor (called samples) will be taken and examined in a lab. This is called a biopsy. Biopsies for suspected sarcomas must be done by healthcare providers with experience treating these tumors. If not done correctly, a biopsy can lead to the tumor spreading, as well as problems taking it out later. The type of biopsy done depends on where the tumor is and how big it is.

Some ways to get a biopsy include:

  • Core needle biopsy. For this test, a healthcare provider puts a hollow needle through your skin and into the tumor. A sample of the tumor is then taken out through the needle. If the tumor is deep in your body, the biopsy is often done using 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 easy to reach, the whole tumor might be taken out. This is called an excisional biopsy. If the tumor is big or the whole thing can't be removed, only a small piece of it might be taken out for testing. This is called an incisional biopsy.

A healthcare provider who specializes in looking at cells, called a pathologist, then looks at the samples under a microscope and runs tests on them. They will find out whether it’s cancer. If it is, other lab tests are done to find out exactly what type of cancer it is and how fast it's growing.

Getting your test results

When your healthcare provider has the results of your tests, they will contact you. 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.

Online Medical Reviewer: L Renee Watson MSN RN
Online Medical Reviewer: Rita Sather RN
Online Medical Reviewer: Todd Gersten MD
Date Last Reviewed: 6/1/2021
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