Soft Tissue Sarcoma

At a Glance

  • Adult soft tissue sarcoma is a disease in which malignant (cancer) cells form in the soft tissues of the body.
  • Estimated new cases and deaths from soft tissue sarcoma in the United States in 2010 are 10,520 and 3,920 respectively.
  • The soft tissues of the body include the muscles, tendons (bands of fiber that connect muscles to bones), fat, blood vessels, lymph vessels, nerves, and tissues around joints.
  • Adult soft tissue sarcomas can form almost anywhere in the body, but are most common in the legs, abdomen, arms, and trunk.

Types of Soft Tissue Sarcoma

There are many types of soft tissue sarcoma. One type that forms in the wall of the stomach, intestines, or rectum is called a gastrointestinal stromal tumor (GIST). The cells of each type of sarcoma look different under a microscope, based on the type of soft tissue in which the cancer began.

Gastrointestinal Stromal Tumor

A gastrointestinal stromal tumor (GIST) is a type of tumor that occurs in the gastrointestinal (GI or digestive) tract, including the esophagus, stomach, gallbladder, liver, small intestine, colon, and rectum. GIST is different from other types of gastrointestinal tumors because of the type of tissues in which it starts.

Risk Factors

Anything that increases your risk of getting a disease is called a risk factor. Risk factors for soft tissue sarcoma include the following inherited disorders:
  • Retinoblastoma.
  • Neurofibromatosis type 1 (von Recklinghausen disease or NF1).
  • Tuberous sclerosis.
  • Familial adenomatous polyposis (FAP).
  • Li-Fraumeni syndrome.
  • Werner syndrome.
  • Basal cell nevus syndrome.
Other risk factors for soft tissue sarcoma include past treatment with radiation therapy during childhood or for the following types of cancer:
  • Retinoblastoma.
  • Breast cancer.
  • Lymphoma.
  • Cervical cancer.


Possible signs of adult soft tissue sarcoma include: A sarcoma may appear as a painless lump under the skin, often on an arm or a leg. Sarcomas that begin in the abdomen may not cause symptoms until they become very large. As the sarcoma grows larger and presses on nearby organs, nerves, muscles, or blood vessels, symptoms may include:
  • Pain.
  • Trouble breathing.

Symptoms of GIST

  • Pain or discomfort in the abdomen
  • A mass in the abdomen that you can feel with your hand
  • Nausea and vomiting
  • Vomiting blood or having blood in the stool
  • Fatigue due to anemia (low red blood cell counts)