Desmoid Tumors

Desmoid tumors are rare benign (noncancerous) tumors that develop in connective tissue. They can develop anywhere in your body, but they typically affect your arms, legs or belly (abdomen). Most grow slowly and don’t cause symptoms. But some fast-growing tumors may affect nearby organs. They can be treated, but often come back.


What is a desmoid tumor?

Desmoid tumors are rare benign (noncancerous) tumors that develop in connective tissue — the network of tissue that supports and connects your bones, ligaments and muscles and keeps your organs in place.

You can have a desmoid tumor anywhere in your body, but they typically affect your arms, legs or belly (abdomen). Other names for desmoid tumors are deep fibromatosis, aggressive fibromatosis or desmoid fibromatosis.

Unlike cancerous tumors, desmoid tumors don’t spread. Most desmoid tumors grow slowly and don’t cause issues. But some are fast-growing and may get big enough to press on tissue, nerves or nearby organs. Healthcare providers can treat desmoid tumors, but they often come back (recur).

Types of desmoid tumors

Healthcare providers categorize desmoid tumors by location. Types include:

  • Abdominal wall desmoid tumors, which affect the wall of tissue that surrounds organs in your belly, like your stomach in your upper abdomen.
  • Intra-abdominal desmoid tumors, which grow in mesentery, the tissue that surrounds your intestines.
  • Extra-abdominal desmoid tumors, which develop in areas other than your belly and abdominal wall. Extra-abdominal desmoid tumors typically develop in your shoulders, upper arms, chest wall and upper legs, but they can also affect your head and neck.


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Symptoms and Causes

What are the symptoms of desmoid tumors?

Desmoid tumors don’t always cause symptoms. When they do, symptoms may include:

  • Pain, soreness or a tingling sensation from a tumor pressing on nearby nerves, organs or blood vessels.
  • A lump or swollen area, usually in your arms, legs and belly.
  • Trouble moving your arm or leg.
  • Nausea and vomiting from a tumor in your belly.

Not every lump or bump is a desmoid tumor, but you should talk to a healthcare provider if you have a lump or bump that’s larger than 2 inches, keeps getting bigger or hurts.

What causes desmoid tumors?

A desmoid tumor develops when connective tissue cells mutate (change) and multiply. Experts aren’t sure what triggers the change, but they have found some risk factors. Risk factors for desmoid tumors include:

  • Having high estrogen.
  • Being assigned female at birth (AFAB).
  • Being pregnant. Pregnancy increases your estrogen levels and stretches your abdominal wall. Most pregnancy-related desmoid tumors develop in your abdominal wall.
  • Having familial adenomatous polyposis (FAP). About 10% of people with FAP develop desmoid tumors.
  • Trauma. Research shows having a serious injury or being repeatedly injured in the same place on your body increases your risk of developing a desmoid tumor.


Diagnosis and Tests

How are desmoid tumors diagnosed?

Your healthcare provider will do a physical examination and ask you about your symptoms. They may recommend the following tests:

Management and Treatment

How are desmoid tumors treated?

Healthcare providers often treat desmoid tumors the same way they treat cancerous tumors. Specific treatment depends on several factors, like tumor size, location and the kind of symptoms it causes. Surgery is the most common treatment. Other treatments include:

  • Active surveillance (watchful waiting): Some desmoid tumors develop but don’t grow large enough to cause symptoms. If you don’t have symptoms, your provider may simply monitor your health and the tumor.
  • Targeted therapy: This treatment works by targeting specific genes or proteins that help desmoid tumors grow. Your provider may recommend treatment using a tyrosine kinase inhibitor (TKI).
  • Cryoablation: Your provider may recommend cryoablation if surgery isn’t an option.
  • Chemotherapy: Oral or intravenous chemotherapy drugs may be used to shrink or eliminate desmoid tumors.
  • Hormone therapy: Tamoxifen may keep desmoid tumors from growing.

What are the treatment side effects?

Treatment side effects vary depending on the treatment type. In general, desmoid tumor treatment side effects may include fatigue from chemotherapy or surgery, or infections that develop after surgery. Your healthcare provider will discuss all treatment side effects, so you know what to expect.


How long does it take to recover from desmoid tumor surgery?

That depends on your situation, but it usually takes two to three weeks to fully recover from desmoid tumor surgery. Your surgeon will explain what you can expect after surgery and how to take care of yourself as you recover.


Can desmoid tumors be prevented?

Desmoid tumors happen when certain genes mutate and create abnormal connective tissue cells. Experts don’t know what triggers this mutation, so there’s nothing you can do to prevent it or prevent desmoid tumors.

Outlook / Prognosis

What are the survival rates of desmoid tumors?

Survival rates depend on several factors, including the size and location of the tumors and how well your body responds to treatment. According to the American Society of Clinical Oncology (ASCO), more than 98% of people with desmoid tumors are still alive five years after their diagnosis.

Can desmoid tumors be cured?

That depends on your situation. Sometimes, surgery to remove a tumor cures the condition. But sometimes, surgeons can’t remove the entire tumor.

Living With

When should I see my healthcare provider?

Desmoid tumors can come back after treatment. Not every lump or bump is a desmoid tumor, but you should talk to a healthcare provider if you have a new lump or bump that’s larger than 2 inches, keeps getting bigger or hurts.

What questions should I ask my healthcare provider?

If you’ve been diagnosed with a desmoid tumor, here are some questions to consider asking your healthcare provider:

  • Where’s the tumor located?
  • How big is it?
  • Is it affecting any of my organs or how my body works?
  • Will I need treatment?
  • If not, how will watchful waiting work?
  • If I need treatment, what are my options?
  • What are treatment side effects?

A note from Cleveland Clinic

Desmoid tumors aren’t cancer, and often, they don’t cause serious medical issues. But fast-growing desmoid tumors can be painful, make you feel nauseated or make it hard for you to move your arms or legs. Fortunately, healthcare providers have treatments that can ease symptoms and sometimes eliminate the tumor.

Medically Reviewed

Last reviewed on 07/28/2023.

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