Soft Tissue Sarcoma

What Is Soft Tissue Sarcoma?

Soft tissue sarcoma is a rare type of cancer that forms in the soft tissues of the body — including muscle, fat, tendons, blood vessels, lymphatic tissue, nerves, and connective tissues around joints. These tumors can occur at any age and in nearly any part of the body, but they most often develop in the arms, legs, chest, or abdomen. Unlike more common cancers, soft tissue sarcomas arise from connective tissues rather than organs.

Causes and Risk Factors

The exact cause of soft tissue sarcoma is often unknown, but several factors may increase risk. These include certain inherited genetic conditions such as Li‑Fraumeni syndrome or neurofibromatosis type 1, previous radiation therapy, and chronic swelling (lymphedema). Genetic changes in the tumor cells themselves drive abnormal growth and may be identified through specialized testing. In children, certain subtypes such as rhabdomyosarcoma are more prevalent.

Signs and Symptoms

Soft tissue sarcomas may grow slowly and may not cause symptoms until they become large. Common signs include:

  • A lump or swelling under the skin that may or may not be painful
  • Pain or discomfort if the tumor presses on nerves or muscles
  • Reduced mobility or limping if near a joint or in a limb
  • Unexplained symptoms depending on location, such as abdominal discomfort

Any persistent or growing mass should be evaluated by a physician.

Diagnosis

Diagnosis begins with a detailed medical history and physical exam. Imaging studies such as MRI, CT scans, or ultrasound help define the size and location of the tumor. A definitive diagnosis requires a biopsy — removing a sample of the tumor tissue — which a pathologist examines under a microscope. Grading and staging help determine how aggressive the tumor is and whether it has spread.

Treatment Options

Treatment of soft tissue sarcoma typically involves a multidisciplinary approach. Options may include:

  • Surgery — Removal of the tumor with a margin of healthy tissue is often the first step and can be curative for localized sarcomas.
  • Radiation therapy — Used before or after surgery to reduce the risk of recurrence, especially for high‑grade tumors.
  • Chemotherapy — Systemic treatment may be used for certain subtypes, larger tumors, or when cancer has spread.
  • Targeted and experimental therapies — In selected cases, newer treatments may be available through clinical trials.

The overall treatment plan depends on the tumor’s type, size, location, grade, and whether it has spread. Close follow‑up care is crucial, particularly in children, as long‑term surveillance helps detect recurrences or late effects of treatment.

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Frequently Asked Questions

Soft tissue sarcoma is a rare cancer that arises in connective tissues such as muscle, fat, blood vessels, nerves, and other soft tissues anywhere in the body.

Symptoms may include a painless or painful lump, swelling, discomfort, or limited movement if a tumor presses on nerves or muscles.

Diagnosis usually involves imaging (like MRI or CT) to assess the tumor and a biopsy to confirm cancer under a microscope.

Treatment often includes surgery to remove the tumor, radiation to prevent recurrence, and sometimes chemotherapy or targeted therapies depending on the subtype and stage of disease.

Yes. Soft tissue sarcoma can spread (metastasize) to other parts of the body, especially the lungs or bones, which is why early detection and complete treatment are important.

The outlook varies by type, location, and how early the sarcoma is detected. Some pediatric sarcomas respond well to treatment, especially when removed surgically before spreading.