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Desmoid tumors Overview
Desmoid tumors are noncancerous growths that occur in the connective tissue. Desmoid tumors most often occur in the arms, legs and abdomen.
Desmoid tumors are tumors that arise from cells called fibroblasts. Fibroblasts are found throughout our body and their main function is to provide structural support and protection to the vital organs such as lung, liver, blood vessels, heart, kidneys, skin, intestines etc. and they also play a critical role in wound healing. When fibroblast cells undergo mutations they can become cancerous and become desmoid tumors (also known as “aggressive fibromatosis”). Desmoid tumors can arise in virtually any part of the body. These tumors often occur in women in their 30’s, but can occur in anyone at any age.
How common is Desmoid Tumor?
Desmoid tumors are rare, affecting an estimated 1 to 2 per 500,000 people worldwide. In the United States, 900 to 1,500 new cases are diagnosed per year. Sporadic desmoid tumors are more common than those associated with familial adenomatous polyposis.
What are the symptoms of Desmoid Tumor?
Desmoid tumors develop in tissue such as tendons and ligaments. These tissues are flexible and easy for tumors to push aside as they grow. So these tumors are often present for a long time before they are found.
Symptoms vary depending on tumor size and location. Common symptoms include the following:
- A painless swelling or lump
- Pain or soreness caused by the tumor pressing on nerves or muscles
- Limping (leg tumors)
- Abdominal (belly) pain, constipation and other problems with the bowel being blocked
- Tingling or the feeling that an area of the body has “gone to sleep” (tumor pressing on a blood vessel or nerve)
Causes of Desmoid Tumor
The cause of most desmoid tumors is unknown and thus they are called “sporadic”. Most desmoids have mutations in a gene called beta catenin.
A minority of desmoid tumors are caused by mutations in a gene called Familial Adenomatous Polyposis or FAP. Patients with mutations in the FAP gene are predisposed to forming hundreds of polyps in the intestines and go on to develop colon cancers. Patients with FAP are often recommended to undergo surgical removal of their intestines. These patients are at a very high risk of developing desmoid tumors which can arise deep in the abdomen or in the abdominal wall. In older scientific literature, the combination of FAP and desmoid tumors is termed Gardner’s Syndrome.
In some rare cases, desmoid tumors can occur in women who are pregnant. This happens during pregnancy or after a surgical delivery. Many believe that this is caused by a combination of elevated hormones and surgery, however, these is no strong scientific evidence to support this claim. The relationship between pregnancy and desmoid tumors is very rare and consists of mostly anecdotes in the scientific literature.
How do people inherit Desmoid Tumor?
Most desmoid tumors are sporadic and are not inherited. Sporadic tumors result from gene mutations that occur during a person’s lifetime, called somatic mutations. A somatic mutation in one copy of the gene is sufficient to cause the disorder. Somatic mutations in either the CTNNB1 or the APC gene can cause sporadic desmoid tumors.
An inherited mutation in one copy of the APC gene causes familial adenomatous polyposis and predisposes affected individuals to develop desmoid tumors. The desmoid tumors occur when a somatic mutation occurs in the second copy of the APC gene. In these cases, the condition is sometimes called hereditary desmoid disease.
How are Desmoid Tumor treated?
If your child has a desmoid tumor, treatment will depend on the patient’s:
- Medical history,
- Overall health,
- Tumor size and expected growth, and
- Ability to withstand treatment.
Desmoid tumor treatment may include surgery, radiation therapy, chemotherapy and antihormonal therapy as well as medicines called nonsteroidal anti-inflammatory drugs (NSAIDs):
- Surgery is the most common way to treat these tumors. They rarely spread (metastasize), so surgery is often the only treatment needed. However, if the tumor is not completely removed or returns, more surgery may be required.
- Radiation therapy uses high-energy X-rays or other types of radiation to kill cancer cells or stop them from growing:
- External radiation uses machines outside the body to deliver the X-ray dose.
- Internal radiation uses needles, seeds, wires or catheters (tubes) to deliver the radiation directly into or close to the cancer.
Radiation therapy may be used alone or in addition to surgery.
- Chemotherapy (“chemo”) uses powerful medicines to kill cancer cells or stop them from growing (dividing) and making more cancer cells.
- Chemo may be injected into the bloodstream, so that it can travel throughout the body.
- Some chemo may be given by mouth.
- Combination therapy uses more than one type of chemo at a time.
Chemo may be used for desmoid tumors that cannot be removed safely because they are too close to blood vessels or other important structures.
- Antihormonal therapy uses medicines that help block the growth of some kinds of desmoid tumors due to the actions of certain hormones (chemicals in the blood).
- Nonsteroidal anti-inflammatory drugs (NSAIDs) may be prescribed to help manage pain and swelling related to desmoid tumors.