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Soft Tissue Sarcoma

Soft tissue sarcoma is a term for cancers that start in the soft tissues of the body. Although sarcoma cancers can develop anywhere, most start in the arms or legs. They can also be found in the chest, internal organs, and abdomen.

Soft tissue sarcoma isn't a common cancer.

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What Is Soft Tissue Sarcoma?  

Soft tissue sarcomas are cancerous tumors that come from the connective tissues, such as fat, muscles, nerves, and tendons.

These sarcomas may be a soft lump that's warm to the touch, and the area around the lump may appear swollen and be tender or painful. But oftentimes, soft tissue sarcomas aren't painful and look like a bruise or lipoma — a benign (noncancerous) fatty lump.

Soft tissue sarcomas often appear in the:

  • Abdomen
  • Arm
  • Buttocks
  • Calf
  • Thigh

How common is soft tissue sarcoma? 

Soft tissue sarcoma is rare, representing only 1% of all adult cancer cases and about 15% of childhood cancer cases.

Of sarcoma occurrence:

  • 40% originate in the lower extremities (legs, ankles, or feet).
  • 30% originate in the trunk, chest wall, abdomen, or pelvis.
  • 15% originate in the upper extremities (arms, hands, shoulders, or wrists).
  • 15% originate in the head and neck.

What are the types of soft tissue sarcoma?

There are more than 50 types of soft tissue sarcomas, and two subtypes.

The two subtypes are:

  • Rhabdomyosarcoma — Occurs in children.
  • Synovial sarcoma — Occurs in teenagers and young adults.

What causes soft tissue sarcoma?  

Scientists aren't sure exactly what leads to most soft tissue sarcomas, but they've identified factors that can make a person more likely to get these cancers. Some of these factors can change the genes in the cells of soft tissues.

What are soft tissue sarcoma risk factors?  

Among the risk factors that may increase your chances of developing soft tissue sarcoma are:

  • Chemicals — Exposure to vinyl chloride, a chemical used in making plastics, is a risk factor for liver sarcomas, but hasn't been proven to cause soft tissue sarcomas. Arsenic is also linked to a type of liver sarcoma, but not to soft tissue sarcoma. High doses of dioxin and herbicides containing phenoxyacetic acid, such as those used in farming, might be risk factors, but this isn't confirmed. There's no evidence that herbicides or insecticides at levels encountered by the general public cause sarcomas.
  • Damaged lymph system — Damage to lymph nodes, often due to radiation therapy, can lead to lymph fluid accumulation, known as lymphedema. In rare cases, chronic lymphedema may result in lymphangiosarcoma, a cancerous tumor developing in lymph vessels.
  • Family cancer syndromes — Some disorders caused by inherited gene mutations may specifically raise the risk of developing soft tissue sarcomas.
  • Gardner syndrome — A condition caused by defects in the APC gene. It's a form of familial adenomatous polyposis (FAP), where people develop numerous polyps in the colon and intestines, leading to a high risk of colon cancer. This syndrome also causes issues outside the colon, such as desmoid tumors.
  • Gorlin syndrome — Also known as nevoid basal cell carcinoma syndrome (NBCCS), Gorlin syndrome is caused by defects in the PTCH1 gene. People with this syndrome are at a high risk of developing numerous basal cell skin cancers, as well as an increased risk of fibrosarcoma and rhabdomyosarcoma.
  • Li-Fraumeni syndrome — Caused by inherited defects in the TP53 gene, this condition increases the risk of cancers like breast cancer, brain tumors, leukemia, and sarcomas. People with Li-Fraumeni syndrome are especially sensitive to radiation, so if they receive radiation treatment for cancer, they have a high chance of developing a new cancer in the treated area. However, only 10% to 20% of those with the syndrome will develop a soft tissue sarcoma.
  • Neurofibromatosis — Also called von Recklinghausen disease, it is often inherited and leads to many noncancerous tumors (known as fibromas) in nerves under the skin and in other body areas. Around 5% of people with neurofibromatosis may develop a sarcoma in a neurofibroma.
  • Radiation given to treat other cancers — People who underwent radiation therapy for conditions like breast cancer or lymphoma might develop sarcoma later in life, typically in the area previously treated. The average timespan between radiation treatment and sarcoma diagnosis is about 10 years. Radiation exposure is responsible for fewer than 5% of sarcomas, a proportion that has been decreasing steadily due to advancements in radiation oncology technology, which allow for more precise targeting.
  • Retinoblastoma — An eye cancer in children caused by defects in the RB1 gene. Kids with this gene defect are also more likely to get bone or soft tissue cancers, especially if their retinoblastoma was treated with radiation.
  • Tuberous sclerosis — People with this condition often experience seizures and learning difficulties. They develop noncancerous tumors in various organs and frequently have kidney issues, including a type of kidney tumor called angiomyolipoma. They also have a higher risk of developing rhabdomyosarcoma.
  • Werner syndrome — Caused by defects in the RECQL2 gene. Children with this condition experience issues typically seen in older adults, such as cataracts, skin changes, and clogged heart arteries, which can lead to heart attacks. They also have a higher risk of developing cancers, including soft tissue sarcomas.

How can I prevent soft tissue sarcoma?

Since most sarcomas occur in people without any known risk factors, there's currently no way to prevent most cases of soft tissue sarcoma. But you can avoid known risk factors whenever possible.

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What Are the Signs and Symptoms of Soft Tissue Sarcoma? 

Symptoms of soft tissue sarcoma may include:

  • A new lump or a lump gradually growing anywhere on your body that may or may not hurt.
  • Worsening abdominal pain.
  • Black, tarry stools (can occur when there's bleeding in the stomach or intestines, causing the blood to turn black and make your poop very dark and sticky).
  • Blood in your stool or vomit.

When sarcomas develop in the back of the abdomen (the retroperitoneum), symptoms often result from issues caused by the tumor. These may include blockages or bleeding in the stomach or intestines; pressure on nerves, blood vessels, or nearby organs; or the tumor growing large enough to be felt in the belly.

When should I see a doctor about my soft tissue sarcoma symptoms?

Although the symptoms of soft tissue sarcoma can be caused by other conditions, too, see your doctor right away if you're having them.

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How Do You Diagnose Soft Tissue Sarcoma?  

Soft tissue sarcoma is serious, but both treatable and curable.

Your doctor will ask about your medical history, including any family history of cancer, to identify potential risk factors. They'll also ask about your symptoms, such as when they began and how long you've had them.

If you have signs or symptoms suggesting a soft tissue sarcoma, your doctor will need to perform tests to determine if you have cancer.

Tests to diagnose soft tissue sarcoma

Tests your doctor may order include:

  • Biopsy — If a soft tissue sarcoma is suspected from exams and imaging tests, a biopsy is needed to confirm the diagnosis. During a biopsy, a small piece of the tumor is removed and examined under a microscope. There are different types of biopsies, and the choice depends on the tumor's size and location. Fine needle aspiration or core needle biopsy is often the first step. Proper biopsy technique is crucial for successfully treating soft tissue sarcomas, as an improper biopsy can lead to tumor spread and complications in removal.
  • CT scans — Use x-rays to create detailed cross-sectional images of your body. They're often used if a soft tissue sarcoma is suspected in the chest, abdomen, or retroperitoneum (the back of the abdomen) and to check if the sarcoma has spread to the lungs, liver, or other organs. CT scans can also guide a biopsy needle into a tumor, known as a CT-guided needle biopsy.
  • Imaging tests — Imaging tests use sound waves, x-rays, magnetic fields, or radioactive substances to create pictures of the inside of your body. These tests may be done to examine suspicious areas for cancer, to check if and how far cancer has spread, and evaluate the effectiveness of treatment.
  • MRI — Uses radio waves and strong magnets instead of x-rays to take body pictures. MRIs are typically better than CT scans for evaluating sarcomas in the arms or legs and provide detailed images of the tumor's size, location, and the type of tissue involved. They're also useful for examining the brain and spinal cord.
  • PET scan — Use radioactive sugar injected into the blood. Because cancer cells absorb sugar at higher rates, the radioactivity collects in the cancer, and a scanner detects these deposits. PET scans can be used to check if cancer has spread and are sometimes combined with CT scans (PET/CT scans) to determine if changes seen on the CT scan are cancerous. PET scans aren't commonly used for sarcomas but can be helpful in certain cases.
  • Ultrasound — Uses sound waves to produce images of body parts. A transducer sends out sound waves and captures the echoes as they bounce off organs. This test can help determine if a lump is a fluid-filled cyst (likely not cancer) or a solid tumor. Ultrasound is often unnecessary if a CT or MRI has been done.
  • X-ray — An initial x-ray of the area with the lump may be ordered. After diagnosis, a chest x-ray may be done to see if the sarcoma has spread to the lungs.

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How Do You Treat Soft Tissue Sarcoma?

Treatment options and prognosis depend on several factors:

  • The type of soft tissue sarcoma.
  • The tumor's size, grade, and stage.
  • The location of the tumor in the body.
  • Whether the entire tumor can be surgically removed.
  • Whether the cancer has recurred.
  • Your age and overall health.

Small, low-grade tumors, particularly those in the trunk, arms, or legs, are often treated successfully with surgery alone. High-grade sarcomas are more challenging to treat and have a higher likelihood of spreading.

Surgery for soft tissue sarcoma

Surgery is the primary treatment for soft tissue sarcoma and may be enough for small, low-grade tumors, particularly those in the trunk, arms, or legs.

The surgical procedures that may be used include:

  • Mohs surgery — A tumor is cut out of the skin in thin layers to remove as little normal tissue as possible. During surgery, each layer of the tumor and its edges are viewed through a microscope. When no more cancer cells are visible, the surgeon closes close the wound. This surgery often is done to minimize scarring in a visible area.
  • Wide local excision — Removes the tumor and some surrounding normal tissue to clear the cancer while retaining as much normal tissue as possible. Neoadjuvant (before surgery) radiation or chemotherapy often is given to shrink the tumor prior to wide local excision surgery.
  • Limb-sparing surgery — Removes a tumor in an arm or leg without amputation, often using grafted tissue or bone to preserve the use and appearance of the limb. 
  • Lymphadenectomy — Also called a lymph node dissection, this procedure removes lymph nodes and tissue, which are viewed under a microscope to check for signs of cancer.
  • Amputation — Surgery to remove part or all of an arm or leg. Fortunately, total amputation is rarely needed to treat soft tissue sarcoma.

Radiation therapy or chemotherapy may be administered before or after surgery to remove the tumor. When given before surgery, these treatments help shrink the tumor, reducing the amount of tissue that needs to be removed. When given after the surgery, the treatments fight any remaining cancer and prevent its return.

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other radiation types to kill cancer cells or stop their growth. There are two types of radiation therapy used to treat soft tissue sarcoma.

They are:

  • External radiation therapy – Uses a machine outside the body to direct radiation toward the cancer area. Intensity-modulated radiation therapy (IMRT) is a type of 3D external therapy that uses a computer to create images of the tumor's size and shape. It uses thin beams of varying intensities aimed at the tumor from multiple angles, minimizing damage to nearby healthy tissue and reducing the likelihood of side effects such as dry mouth, difficulty swallowing, and skin damage.
  • Internal radiation therapy — Involves placing a radioactive substance sealed in needles, seeds, wires, or catheters directly into or near the cancer.

The type of radiation therapy your doctor recommends will depend on the type and stage of your cancer.


Chemotherapy uses drugs to stop cancer cells from growing by either destroying them or preventing them from dividing. When taken orally or injected into a vein or muscle, these drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy).

Targeted therapy

Targeted therapy uses medications and other substances to identify and attack specific cancer cells.  

The different types of targeted therapy include:

  • Tyrosine kinase inhibitors — Block the signals cancer cells need to grow and divide.
  • Histone methyltransferase inhibitors — Help keep cancer cells from growing. 


Immunotherapy uses a person’s own immune system to fight cancer. Immunity-boosting substances made by the body or in a lab are reinforced and administered back into the patient’s body to restore and bolster the body's natural defenses against cancer.

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