Sarcoma is a type of cancer that originates in the bones or soft tissue. Soft tissue sarcoma (STS) most often begins in the arms and legs but can also occur in other body parts.

Soft tissues include fat, muscle, fibrous tissue, blood vessels, lymph vessels, and nerves.

STS can begin to form tumors in any of these soft tissues. Because of this, STS tumors can be present in the leg.

This article looks at STS in the leg, symptoms, diagnosis, and more.

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STS tumors can occur anywhere in the body, but more than half develop in a person’s arm or leg. There are more than 50 types of STS.

The types that most commonly occur in the leg include:

  • alveolar soft-part sarcoma
  • clear cell sarcoma
  • epithelioid sarcoma
  • fibromyxoid sarcoma, low grade
  • leiomyosarcoma
  • myxofibrosarcomas, low grade
  • undifferentiated pleomorphic sarcoma

Most people with STS experience swelling or a lump that continues to grow for weeks or months. This lump may be present in the leg.

STS in the leg can cause a lump that:

  • feels painful or tender
  • continues to get bigger
  • grows larger than 2 inches, or about the size of a golf ball

However, the lump may or may not be painful. The absence of pain does not indicate that the lump is benign, so a person must contact a healthcare professional if they notice any new or growing lumps on their body.

It is important for doctors to diagnose STS in the leg as early as possible to prevent it from spreading.

A doctor will ask a person about their medical history and symptoms. They may also perform a physical exam.

After this, they may use imaging technology and biopsies to diagnose STS.

Imaging tests

Imaging tests, such as X-rays and CT scans, produce images of the inside of a person’s body. These can help a doctor determine the size and location of the tumor, which will be useful for planning treatment.

An MRI scan is the imaging test of choice for determining the size, location, and extent of an STS tumor.

Other imaging tests doctors may use to diagnose STS in the leg include X-rays and ultrasound scans. They may perform these in one area.

If they find STS in the leg, a doctor may recommend a chest X-ray to check whether the cancer has spread to the lungs.

Biopsy

A biopsy is a minor procedure in which a healthcare professional removes a small amount of tissue for examination under a microscope.

Doctors can use a biopsy to diagnose STS in the leg.

The outlook for STS in the leg depends on several factors, including:

  • the stage of cancer at diagnosis
  • a person’s overall health
  • how deep the tumor is
  • the treatment a person receives
  • how the STS responds to treatment

If doctors catch STS early, the outlook is typically favorable. STS in the arm or leg or on the surface of the trunk usually has a better outlook than STS that starts in other body parts.

The table below shows the survival rates for STS. The information is from people who received an STS diagnosis between 2010 and 2016.

SEER stageStage description 5-year relative survival rate
localizedCancer is present only in the part of the body where it started, such as the leg. 81%
regionalCancer has spread from the leg to nearby structures or lymph nodes.56%
distantCancer has spread from the leg to distant organs or body parts, such as the lungs.15%
all SEER stages combinedThis is the average survival rate for all the above stages combined. 65%

A 5-year relative survival rate compares people with the same type and stage of STS to those in the general population.

For example, a person with localized STS is, on average, around 81% as likely to live for 5 years after diagnosis as someone without STS is to live for those 5 years.

It is important to note that these figures are based on statistics from previous years. As treatment improves, people may have a better outlook than those who received a diagnosis 5 or more years ago.

Read on to learn about some of the most commonly asked questions about STS in the leg.

What does sarcoma in the leg feel like?

STS in the leg may feel like swelling or a lump in the leg that continues to grow.

The lump may feel painful or tender, or it may be painless. Over a period of weeks or months, it may grow to be bigger than 2 inches, about the size of a golf ball.

People may often develop this lump deep in the body tissues, so it may not be obvious at first.

Is sarcoma on the leg curable?

Whether STS in the leg is curable depends on the type and stage of the cancer at diagnosis.

It is possible to cure early stage sarcomas using surgery alone. More advanced sarcomas may require further treatment, such as chemotherapy or radiation therapy.

STS in the leg or arm or on the surface of the trunk may have a better outlook than STS that starts in other body areas.

How fast does sarcoma in the leg grow?

STS in the leg may grow over a period of weeks to months. The growth rate of STS varies from case to case — it can grow quickly or slowly.

STS is an uncommon type of cancer that starts in soft tissues such as fat, muscle, fibrous tissue, cartilage, blood vessels, lymph vessels, and nerves.

Therefore, STS can start in the leg.

The main symptom of STS in the leg is swelling or a lump in the area. The lump may be painless or feel tender and may continue growing for weeks or months.