What is sarcoma?
A sarcoma is a type of tumor that develops in connective tissue, such as bone, cartilage or muscle. Malignant sarcoma are very rare (1% of all adult malignancies and about 15% of childhood malignancies). Approximately 14,000 to 15,000 sarcomas are diagnosed in the United States every year (3,000 bone sarcomas and 11,000 to 12,000 soft tissue sarcomas).
Sarcomas appear in the body in the following percentages:
- 40% occur in the lower extremities;
- 15% in the upper extremities;
- 30% in the trunk/chest wall/abdominal locations;
- 15% in the head and neck region.
Conditions that can be mistaken for tumors
Many conditions can be mistaken for tumors. Everyone has occasional lumps and bumps, and it is important to be able to tell the difference between those masses that might be cancerous and those that occur because of injury, congenital growths or the normal aging process. For instance, in the skeleton, stress fractures, chronic infections and benign bone tumors might appear to be malignant.
What are the types of sarcoma?
Benign bone tumors
Benign (noncancerous) tumors are even more common than malignant tumors in the musculoskeletal system.
Common types of benign tumors include:
- Aneurysmal bone cysts.
- Simple bone cysts.
- Fibrous dysplasia.
- Langerhans Cell Histiocytosis.
- Non-ossifying fibromas.
In addition, benign bone tumors can be associated with familial conditions or syndromes, such as MHE (multiple hereditary exostosis), Ollier’s Disease, Maffucci’s Disease or McCune-Albright syndrome.
Benign bone tumors that are more aggressive, such as giant cell tumor or chondromyxoid fibromas, usually require surgery. In these cases, techniques such as synthetic bone graft substitutes are used to rebuild rather than remove bone. Drugs such as denosumab or doxycycline are also used to treat specific tumors.
Malignant bone tumors
Though bone tumors are a rare type of cancer (approximately 3,000 cases a year in the United States), there are many different types.
Common types of malignant bone tumors include:
More than one-third of bone sarcomas are diagnosed in patients under the age of 35 years old; many are diagnosed in children.
Metastatic bone tumors
As opposed to primary bone sarcoma (cancer that starts in the bone), metastatic bone cancer starts in another location (such as an organ) and travels to the bone. This cancer comes in many forms, most often thyroid, lung, kidney, breast or prostate.
When a cancer from a distant organ spreads to the skeleton, it can create structural problems in the bone that may lead to greater pain and reduced functioning.
Soft Tissue Tumors
Benign soft tissue tumors
Benign soft tissue tumors are very common (fewer than 5% of all lumps or bumps discovered are cancerous). Many of these tumors can be monitored regularly, but some have to be removed by surgery. Some benign tumors, such as desmoid tumors, may require treatment from the medical oncology, radiation oncology or interventional radiology teams, all of which work closely together.
The most common types of benign soft tissue tumors include:
- Desmoid tumors.
- Large arteriovenous malformations.
- Lipomas (fatty tumors).
- Pigmented villonodular synovitis.
- Synovial chondromatosis.
Malignant soft tissue tumors
Soft tissue sarcomas begin in the muscle or other connective tissues of the body. Unlike bone tumors, most soft tissue sarcomas occur in adults, though certain types, such as rhabdomyosarcoma, are found mostly in children.
Some of the most common types of soft tissue sarcomas include:
- Desmoplastic small round cell tumors.
- Gastrointestinal stromal tumor (GIST).
- Malignant peripheral nerve sheath tumor.
- Synovial sarcoma.
- Undifferentiated pleomorphic sarcoma.
What are the symptoms of sarcoma?
The symptoms of sarcomas vary. For example, in their early stages, some sarcomas may not cause noticeable symptoms. Sarcomas may appear as a painless lump under the skin. Other sarcomas may form in the abdomen, and may not cause symptoms until they grow very large and press on an organ.
Other sarcomas can present as long-lasting bone pain or swelling in an arm or leg that gets worse at night, or decreased mobility.
Sarcoma symptoms that should be investigated are masses (growths) that grow larger, painless masses that have become painful or masses larger than a golf ball (around five centimeters).
In the case of children, a child who has bone pain that does not get better on its own, and that did not occur with an injury, should have an imaging test to investigate.