Soft tissue sarcomas are a group of rare cancers that develop in soft tissues, such as muscle, fat, or nerves. They can develop in almost any part of your body.

The American Cancer Society estimates that about 13,400 people in the United States will receive a soft tissue sarcoma diagnosis in 2023.

More than 60 types have been identified. The most common locations they develop are:

  • arms and legs: 60%
  • trunk: 19%
  • area behind the abdominal cavity (retroperitoneum): 15%
  • head and neck: 9%

In this article, we examine the most frequently diagnosed types of soft tissue sarcomas, including how common they are, where they develop, and the outlook for people who have them.

Leiomyosarcoma and liposarcoma are the most common types of soft tissue sarcoma. A 2018 study using data from regional German cancer registries estimates the rate of leiomyosarcoma is approximately 11.5 people per million per year.

In the United States, based on data collected from 2015–2019, the rate of new cases of soft tissue sarcoma was about 3.4 per 100,000 people per year.

Leiomyosarcoma arises from smooth muscle cells, which control involuntary actions, such as moving food through your digestive tract. It can develop almost anywhere in your body but most commonly develops in the uterus or abdomen.

Leiomyosarcoma is most common in adults over age 60 years.

Leiomyosarcoma of the uterus most often develops during menopause.

Leiomyosarcoma survival rates

Leiomyosarcoma tends to be aggressive, but people who have it usually have a better outlook when it develops in one of their limbs instead of inside their abdomen.

A 2021 study found that the 10-year disease-specific survival was 90% when it developed in the skin or layer of tissue below your skin.

The 5-year survival rate ranges from about 31–66.7% in people who develop leiomyosarcoma in the major blood vessel that returns blood to the heart.

In the United States, people with leiomyosarcoma diagnosed in 2012–2018 had a 5-year relative survival rate of about 38%.

The 5-year relative survival rate is a measure of how many people with the cancer are alive 5 years later compared to people without the cancer.

Liposarcoma makes up less than 20% of soft tissue sarcomas. It arises from fat cells in tissues, such as in your:

Data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program from 2001–2016 suggests that liposarcoma may affect about 10.8 people per million per year. Rates are nearly twice as high among males as females. The most common age range seems to be 50–65 years.

The outlook for people with liposarcoma varies greatly between subtypes. The 5-year survival rate has been reported as 58–95%.

Gastrointestinal stromal tumors (GISTs) start in special cells in the wall of your gastrointestinal tract called interstitial cells of Cajal. They’re estimated to affect 3.2–6.8 people per million per year in the United States.

About 30% of GISTs are cancerous. They can occur in any part of your GI tract. About 60% occur in the stomach.

About half of people are in their 60s or older when they receive a diagnosis. The 5-year relative survival rate of people with GISTs is about 85%.

Undifferentiated pleomorphic sarcoma (UPS) was previously known as malignant fibrous histiocytoma. It’s the fourth most common type of soft tissue sarcoma and occurs in anywhere from 0.8–10 people per million per year.

UPS is an aggressive and fast-growing cancer. It typically starts as a rapidly growing tumor on or below your skin without causing changes to the surface of your skin. It most often develops in your arms or legs.

The chances of developing UPS increase with age. It’s most common in people in their 60s or older. The 5- and 10-year overall survival rates have been reported as 60% and 48%, respectively.

Synovial sarcoma can develop anywhere in your body. It’s associated with a translocation between chromosomes X and 18. A translocation is when a chromosome breaks and the pieces reattach to another chromosome.

Rates of synovial sarcoma in the United States are estimated to be about 1.77 per million people per year. Unlike many other cancers, synovial sarcoma is most common in adolescents and adults under age 30.

Synovial sarcoma tends to be aggressive. People with this type of soft tissue sarcoma generally have a poor outlook. The chances of surviving at least 5 years have been reported as 50–60% for adults.

Other types of soft tissue sarcomas include:

  • Malignant peripheral nerve sheath tumors (MPNST): MPNSTs develop in the tissue that covers nerves outside of your brain and spinal cord. It’s extremely rare overall, but the lifetime risk is about 10% in people with a genetic condition called neurofibromatosis type 1.
  • Fibroblastic sarcoma: Fibroblastic sarcoma is a very rare type of soft tissue sarcoma. It develops in cells that produce connective tissue. About 55% of people with fibroblastic sarcoma are alive 5 years after receiving a diagnosis.
  • Kaposi sarcoma: Kaposi sarcoma starts in the cells that line your lymph and blood vessels. It most often occurs in people with immunosuppression, such as organ transplant recipients and people with stage 3 HIV.
  • Rhabdomyosarcoma: Rhabdomyosarcoma is the most common type of soft tissue sarcoma in children. It develops in muscle tissue.
  • Desmoplastic small round cell tumors: Desmoplastic small round cell tumors are extremely rare tumors that usually develop in adolescents and young adults. They usually develop in the abdomen.

Which types of soft tissue sarcomas are the most aggressive?

The 5-year relative survival rate of people with a diagnosis of soft tissue sarcoma in the United States from 2010–2016 was 65% based on the National Cancer Institute’s SEER data.

In a 2018 study, researchers reported the survival rates of people in four European countries with a diagnosis of six subtypes of soft tissue sarcoma and an “other” category.

Researchers reported the lowest survival rate among people with synovial sarcoma and the second lowest in people with liposarcoma.

Soft tissue sarcoma is a group of cancers that develop in your body’s soft tissue. The three most common types are:

  • leiomyosarcoma
  • liposarcoma
  • gastrointestinal stromal tumors

These cancers develop in smooth muscle, fat cells, and cells that line your gastrointestinal tract, respectively.

The outlook for people with soft tissue sarcomas vary between subtypes. Liposarcomas and synovial sarcomas seem to be among the most aggressive subtypes.