Sarcoma: causes and symptoms
Sarcomas affect certain tissues, including bone, skin and other soft tissues. This article 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.
What is sarcoma?
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.
Sarcomas are a relatively rare type of cancer, accounting for around just 1% of all cancers, although their incidence has risen over recent decades. Around 12,000 cases of soft tissue sarcoma are diagnosed annually in the US, and experts estimate that almost 40% of these are fatal.
Several soft tissue sarcomas have been identified and are defined according to the specific tissue or location affected.
The following are the most common types of soft tissue sarcoma:
- 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.
The causes of sarcoma
Only one type of soft tissue sarcoma has a clearly known cause: Kaposi's sarcoma, a cancer caused by the human herpes virus 8.
High doses of radiation, for example from a previous cancer therapy, are a clear risk factor for soft tissue sarcomas.
For most types of soft tissue sarcoma, however, the cause is not known at all, although in some cases it can be associated with certain genetic conditions.
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.
Symptoms of soft tissue sarcoma
Soft tissue sarcomas can often be asymptomatic - the tissue is often loose enough to accommodate the lump without it being noticed.
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.
Specific symptoms may reflect the particular type of sarcoma. Rhabdomyosarcoma, for example, may present symptoms that reflect the particular location affected:
• 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.
Author: Markus MacGill / Nov. 2015
Text abridged and adapted / Feb. 16
With kind permission to publish from MNT
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