Sarah Cannon - August 23, 2021

Sarcoma is a term for cancers that begin in the bones or soft tissues of the body, including the muscles, fat, lymph and blood vessels, nerves and tendons. While sarcoma can occur anywhere in the body, it is most common in the chest, abdomen, arms and legs.

Approximately 60% of sarcomas start in the arm or leg, 30% begin in the abdomen and 10% first develop in the head or neck.

Sarcoma is rare in adults, representing only about 1% of adult cancers. It’s more common in children, accounting for 15% of childhood cancers.

Sarcoma is divided into two main categories:

  • Soft tissue sarcoma (STS)
  • Sarcoma of the bone, or bone cancer

This article will focus on soft tissue sarcomas.

What causes sarcoma?

While experts don’t know what causes sarcomas, some factors may increase your risk, including:

  • Radiation treatment for other cancers
  • Family cancer syndromes caused by gene defects, such as Gardner syndrome, Gorlin syndrome, Li-Fraumeni syndrome, neurofibromatosis, retinoblastoma, tuberous sclerosis and Werner syndrome.
  • Damage to the lymph system
  • Certain chemicals 

Symptoms of sarcoma

Symptoms can vary based on the type of sarcoma you have. Soft tissue sarcoma usually doesn’t cause any symptoms in its earlier stages, so it can go unnoticed. But as the tumor grows, it can lead to pain and disrupt normal bodily functions.

Sarcoma symptoms can include:

  • A new or growing lump anywhere on your body
  • Blood in your vomit or stool
  • Worsening abdominal pain
  • Black, sticky-looking stool

These symptoms can be caused by other conditions, not just sarcomas. It’s important to see your doctor right away if you have any of these warning signs.

How is sarcoma diagnosed?

If your doctor suspects sarcoma, they will likely take a biopsy for testing. During a biopsy, your physician will take a small sample of tissue from the affected area. This tissue will be examined by a pathologist.

The pathologist can run tests to determine the type of sarcoma and its grade, which is how much the cancer cells resemble healthy cells under a microscope. These tests can help your physician recommend the best treatment approach for you.

Your doctor may also recommend additional tests, such as an:

  • Ultrasound
  • Computed tomography (CT) scan
  • Magnetic resonance imaging (MRI)
  • X-ray
  • Positron emission tomography (PET) scan

Sarcoma staging and grades

The stage of a sarcoma describes where the cancer is located and if and where it has spread. Doctors typically use the TNM system to diagnose sarcomas:

  • Tumor (T): Where is the tumor located? How large is it?
  • Node: Has the cancer spread to the lymph nodes? If it has, which and how many lymph nodes are affected?
  • Metastasis: Has the cancer spread to other areas of the body? If so, where?

Your pathologist will also determine the sarcoma’s grade, which is how closely the tumor cells do or don’t resemble healthy cells. The higher the tumor grade, the more abnormal the cells appear and the more aggressive the sarcoma may be. A lower-grade sarcoma may be less likely to grow quickly, spread and return after treatment. 

The TNM results and grade are then used to determine the stage:

  • Stage I: The tumor is low-grade and small.
  • Stage II: The tumor is higher-grade and small.
  • Stage III: The tumor is higher-grade and larger.
  • Stage IV: The tumor has spread to other areas of the body.

Sarcoma diagnosis next steps

If you’ve been diagnosed with sarcoma, the next steps depend on the type of sarcoma, along with its stage and grade. Learn more about sarcoma treatment options.

If you have questions about coping with scan anxiety, call askSARAH at (844) 482-4812 or visit askSARAH online.


American Cancer Society
National Cancer Institute

It is important to know that the information in this post, including Sarah Cannon’s recommendations for screening, is accurate as of the publishing date.