Sarcomas affect certain tissues, including bone, skin and other soft tissues. This page explains soft tissue sarcomas in particular, which range through numerous types that can originate in any part of the body and affect children as well as adults.
Use this page for detailed but easy-to-understand information about soft tissue sarcoma.
Contents of this article:
There are introductions at the ends of some sections to recent developments that have been covered by MNT's news stories. Also look out for links to information about related conditions.
Sarcoma of the bone includes osteosarcoma, Ewing sarcoma and chondrosarcoma - for more information about these, see the MNT page dedicated to bone cancer.
A sarcoma that affects the skin and is caused by a virus is given detailed coverage on a page dedicated to Kaposi's sarcoma.
Fast facts on sarcoma
Here are some key points about soft tissue sarcoma. More detail and supporting information is in the body of this article.
- Soft tissue sarcomas are relatively rare tumors that affect tissues connecting, supporting or surrounding any of the body systems.
- There are over 50 types of soft tissue sarcoma.
- Common forms of sarcoma include undifferentiated pleomorphic sarcoma, gastrointestinal stromal tumor, liposarcoma, leiomyosarcoma and synovial sarcomas.
- Symptoms may not be apparent - the only sign of sarcoma may be a palpable lump.
- Pain can result from the tumor's location or its effect on nearby nerves.
- After history-taking and a medical examination, medical imaging scans will help to inform a diagnosis, which can be confirmed definitively through laboratory analysis of a tumor sample.
- Treatment, as for other forms of cancer, can take numerous forms, including surgery, radiation therapy and chemotherapy.
- As the causes of sarcoma are largely unknown, prevention is not possible, except that reducing exposure to certain risk factors, such as radiation, may be important.
What is sarcoma?
A sarcoma lump can be symptomless and may go unnoticed until it is big enough or its location impacts local muscle or nerves, for example.
Sarcoma is a tumor that affects connective tissue. Soft tissue sarcomas, as the name suggests, affect the soft tissues - those that connect, support and surround body systems. Soft tissues include fat, muscle, blood vessels, deep skin tissues, cartilage, tendons and ligaments.1,2
Sarcomas are relatively rare types of cancer, accounting for around just 1% of all cancers, although their incidence has risen over recent decades.1,3 Around 12,000 cases of soft tissue sarcoma are diagnosed annually in the US, and experts estimate that almost 40% of these are fatal.1
There is a long list of different types of soft tissue sarcoma, defined by the specific tissue or location affected.4-5
The following are the most common types of soft tissue sarcoma:4-6
- Undifferentiated pleomorphic sarcoma - previously known as malignant fibrous histiocytoma - this tumor is most often found in the arms or legs but sometimes at the back of the abdomen
- Gastrointestinal stromal tumor (GIST) affects specialized neuromuscular cells of the gut
- Liposarcoma is sarcoma of fat tissue
- Leiomyosarcoma affects smooth muscle (in organ walls)
- Synovial sarcomas are usually found in the arms or legs around a joint capsule
- Malignant peripheral nerve sheath tumor, also known as neurofibrosarcoma, affects the protective lining of the nerves.
Rhabdomyosarcoma forms in muscle and is a childhood cancer. While rare overall, it is a relatively common tumor in children.7
Other examples of soft tissue sarcoma include angiosarcomas developing in the cells of the blood or lymph vessels, and fibrosarcomas, which usually form in the limbs or on the trunk, forming from fibroblasts, the most common cell type in connective tissue.2,3,5
Further examples - the full list runs to more than 50 types - include dermatofibrosarcoma protuberans, a skin lesion; epithelioid sarcoma, which often affects young adults' hands or feet; myxoma, which affects older adults, usually in the arms and legs; mesenchymomas, which are rare and combine elements of other sarcomas and can be found in any part of the body; vascular sarcomas, containing many blood vessels; and malignant neurilemmoma (also known as schwannoma).3,4
There is an MNT page dedicated to Kaposi's sarcoma, which often affects the skin.
A whole medical journal is dedicated entirely to research on sarcomas, entitled Sarcoma, appropriately enough.
Causes of sarcoma
Only one type of soft tissue sarcoma has a clearly known cause - MNT has a page dedicated to Kaposi's sarcoma, a cancer caused by the human herpesvirus 8.
High doses of radiation, for example as previous cancer therapy, are a clear risk factor for soft tissue sarcomas.1-3
For most types of soft tissue sarcoma, however, the cause is not known at all, although for some there can be an association with certain genetic conditions.2
There are other risk factors, too, including age, which is associated with cancer in general. Increased risks of sarcoma have also been observed in relation to exposure to certain chemicals, including vinyl chloride, dioxins and phenoxyacetic herbicides.2
Recent developments on sarcoma from MNT news
Trabectedin (brand named Yondelis) was approved by the US Food and Drug Administration (FDA) in October 2015 for use as a chemotherapy drug for treating liposarcoma and leiomyosarcoma.
Phase III clinical trials of eribulin (brand named Halaven) showed it had promise against advanced leiomyosarcoma and liposarcoma in findings published in October 2015.
In clinical trials in people with advanced soft tissue sarcoma, published in the summer of 2015, the drug pazopanib was found to improve quality of life.
Symptoms of soft tissue sarcoma
People with soft tissue sarcomas can often go without symptoms - the tissue is often loose enough to accommodate the lump without it being noticed.3
Soft tissue sarcoma may not produce any signs until a lump grows to a larger size that can be palpated, and even this may go unnoticed until the tumor affects local tissues, nerves or muscles in a way that causes pain.3
Specific symptoms may reflect the particular type of sarcoma. Rhabdomyosarcoma, for example, may present symptoms that reflect the particular location affected:7
- If the eye is affected, it can cause pain or even eye protrusion. Nasopharyngeal cavity tumors may also cause pain, as well as nasal congestion, discharge and changes to the voice
- Abdominal pain or difficulty urinating can be caused by the genitourinary form of rhabdomyosarcoma.
Tumors in the gastrointestinal system may bleed, so these sarcomas may be indicated by the sign of blood in the stool, or a stool that has a black, tarry appearance.4
On the next page, we look at tests and diagnosis of sarcoma, along with its prevention and treatment.