Soft tissue sarcoma is a type of tumor that forms in the soft tissues of the body, such as muscle, fat, fibrous tissue, and blood vessels. It can occur in various places, including the shoulder.

Most soft tissue sarcomas start in the arms or legs, but they can spread to other areas.

This article looks at soft tissue sarcoma in the shoulder and its symptoms and diagnosis.

We also discuss the outlook for people with the condition and more.

To discover more evidence-based information and resources for cancer, visit our dedicated hub.

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Soft tissue sarcomas can occur in the shoulder because they can form in any soft tissue. This includes:

  • fat
  • muscle
  • fibrous tissue
  • deep skin tissue
  • nerves
  • blood vessels

Common locations for soft tissue sarcomas include the arms and the legs. Soft tissue sarcomas can also occur in the:

  • abdomen
  • torso
  • head and neck
  • internal organs

Soft tissue sarcomas are rare, making up around 1 in 100 of all tumors.

Synovial sarcoma

Synovial sarcoma is a type of soft tissue sarcoma that affects the tissue surrounding the joints. It is common for synovial sarcoma to occur in the shoulder.

This is because it forms in soft tissue, such as the muscles or ligaments, and usually occurs near joints.

Synovial sarcoma also commonly occurs in the:

  • shoulder
  • hip
  • knee
  • ankle

Synovial sarcoma most commonly affects children and young adults, but it can also affect older people.

Symptoms of soft tissue sarcoma in the shoulder may include a painless lump or swelling under the skin. If the tumor is pressing on a nerve, it can cause shoulder pain or numbness in the shoulder.

As a sarcoma grows, it may press on surrounding muscles or blood vessels, and people can feel pain and have difficulty breathing.

To diagnose soft tissue sarcoma in the shoulder, doctors may carry out the following:

  • Imaging tests: A doctor may use imaging scans such as a CT scan, MRI, X-ray, and ultrasound to see if a tumor is present.
  • Biopsy: A doctor will use a technique known as a core needle biopsy. This uses a needle to remove a small sample of tissue that the doctor sends for laboratory testing to check for cancer and tumor grade.

The main types of treatment for soft tissue sarcoma include:

Some soft tissue sarcomas may only require treatment with surgery.

Small, low-grade soft tissue sarcomas, particularly those that form in the arms, usually only require treatment with surgery.

The outlook for soft tissue sarcoma in the shoulder may depend on various factors, such as:

  • whether the cancer has spread to other parts of the body
  • how much of the tumor surgery can remove
  • the type, size, and grade of the soft tissue sarcoma
  • whether the cancer has come back
  • the person’s age and overall health

According to the National Cancer Institute, soft tissue sarcomas and synovial sarcomas are rare, which makes it more difficult to accurately predict survival rates.

Survival rates also do not take into account advances in treatments and newer research.

Between 36% and 76% of people with synovial sarcoma will survive at least five years after first receiving a diagnosis.

Complete removal of the tumor, and a tumor that does not spread or return, may improve the outlook.

This section answers some common questions about soft tissue sarcoma in the shoulder.

Can you get a tumor in your shoulder?

It is possible to get a tumor in the shoulder. Synovial sarcoma is a type of soft tissue tumor that commonly forms in the shoulder.

Synovial sarcoma is a rare type of cancer. Synovial sarcomas may make up 5–10% of all soft tissue sarcomas. In the United States, 1–2 people out of one million have a diagnosis of synovial sarcoma yearly.

Where does sarcoma usually start?

The most common place for soft tissue sarcomas to start developing is in the arms or the legs, with these areas accounting for around 50–60% of soft tissue sarcomas.

The next most common place for soft tissue sarcomas to develop is the torso, with this accounting for 19% of soft tissue sarcomas.

What does a sarcoma lump feel like?

A sarcoma lump may feel like a painless swelling or lump underneath the skin.

As a sarcoma grows, it may begin to press on surrounding nerves, organs, blood vessels, or muscles. This can cause pain, and people may have trouble breathing.

Soft tissue sarcoma is a rare type of cancer that forms in the soft tissues of the body.

Synovial sarcoma is a type of soft tissue sarcoma and commonly affects the shoulder. People may feel a painless lump or swelling under the skin. A sarcoma can cause pain if it presses on nearby nerves or muscles.

People may have surgery to remove the tumor. Doctors can also use radiation therapy or chemotherapy to treat soft tissue sarcoma. Complete removal of the tumor may improve a person’s outlook.