Desmoid Tumors

  • What are desmoid tumors?

    Desmoid tumors are among the rarest tumors in the United States, affecting only 2-4 people per million. Also known as aggressive fibromatosis, desmoid tumors are part of a group of malignant soft-tissue sarcomas.

    Desmoid tumors typically look like as single defined, firm but rubbery mass, much like scar tissue. The slowly growing mass forms in the body’s connective tissue — often in the arms, legs or trunk, and sometimes in the abdomen or thorax (rib cage).

    Often painless, desmoid tumors can be present in the body for a long period of time before they are discovered. Because of this, young adults are more likely than children to be diagnosed with desmoid tumors.

  • Causes

    The cause of desmoid tumors is unknown, but there may be a genetic reason for their formation.

  • Signs and symptoms

    Symptoms of a desmoid tumor may include:

    • Painless swelling or a lump
    • Pain or soreness due to the tumor compressing nerves or muscles
    • A limp
    • Difficulty moving legs or arms
  • Testing and diagnosis

    Symptoms of desmoid tumors can be difficult to identify in children and teens, so regular check-ups are extremely important. Prompt diagnosis is crucial to overall treatment.

    Diagnostic evaluation begins with a thorough medical history and physical examination of your child. A detailed neurological assessment may also be performed.

    At The Children’s Hospital of Philadelphia, clinical experts in the Cancer Center and Division of Orthopedics use a variety of diagnostic tests to diagnose desmoid tumors, including:

    • X-rays, which produce images of bones.
    • Magnetic resonance imaging (MRI), which uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body.
    • Computed tomography (CT) scan, which uses a combination of X-rays and computer technology to produce cross-sectional images ("slices") of the body.
    • Radioisotope bone scan, which can help locate areas of abnormal growth.
    • Blood tests, which can help determine drug usage and effectiveness, biochemical diseases and organ function.
    • Biopsy, which is a surgical procedure to take a sample of the growth, may be necessary to confirm any findings.
    • EOS imaging, a newly FDA-approved imaging technology which creates 3-dimensional models from two planar images. Unlike a CT scan, EOS images are taken while the child is in an upright or standing position, enabling improved diagnosis due to weight-bearing positioning.
  • Treatments

    Treatment for desmoid tumors varies, depending on the location and size of the tumor.  In most cases, treatment involves a combination of surgery, radiation therapy and chemotherapy.


    Desmoid tumors can be difficult to remove because they intertwine with the tissues and organs around them. It is not always possible for surgeons to locate the boundaries of the tumor when they are removing it. This makes the rate of desmoid tumor recurrence as high as 70 percent.

    However, surgical removal of the tumors remains the optimal therapy. Surgeries performed are typically:

    • Wide resection with margins
    • Resection and reconstruction

    In a wide resection with margins, the tumor is surgically removed, as well as some of the healthy tissue that surrounded the tumor — the margins of the tumor. In some cases, the child will need reconstructive surgery after the tumor has been cut out.

    Radiation therapy and chemotherapy

    Radiation therapy and chemotherapy are sometimes utilized for the treatment of desmoid tumors. Sometimes both surgery and radiation are used. When chemotherapy is used, the drugs are given in low doses. There are few short-term side effects and almost no long-term side effects.

    • Chemotherapy: Refers to medicines — given by mouth, in the vein, in the muscle or under the skin — that help fight tumors. 
    • Radiation therapy: Uses high-energy waves such as X-rays to kill or shrink tumor cells.
  • Follow-up care

    Most children who had surgery to treat a desmoid tumor are able to go home shortly after surgery. They may require pain medications until the surgical site heals or ongoing physical therapy, but most are encouraged to resume their regular daily activities, like school, social events and play.

    Your child will need to follow-up with the surgeon one to two weeks after surgery, then again at three and six months post-surgery. Annual monitoring by trained clinicians is strongly encouraged to monitor for possible reoccurrence of the growth.

    Desmoid tumors have a high rate of recurrence — even after being successfully treated — so it is important for your child to see a physician regularly. 

    During follow-up visits, X-rays and other diagnostic testing of the tumor site are recommended to closely monitor your child’s health and ensure there are no side effects from surgery, chemotherapy or radiation therapy.

    Follow-up care and ongoing support and services are available at our Main Campus and throughout our CHOP Care Network. Our team is committed to partnering with parents and referring physicians to provide the most current, comprehensive and specialized care possible for your child.

Reviewed on May 15, 2013