Soft Tissue Sarcoma

Overview :

Sarcoma is a type of cancer that develops in bones or soft tissues.Soft tissue includes:

blood vessels
nerves
tendons
muscles
fat
fibrous tissue
the lower layers of the skin (not the outer layer)
the lining of the joints

Sarcomas of soft tissue are relatively uncommon. Sarcomas can be life-threatening, especially if they’re diagnosed when a tumor is already large or has spread to other tissues.

Soft tissue sarcomas are most often found in the arms or legs, but can also be found in the trunk, internal organs, head and neck, and the back of the abdominal cavity.

There are many kinds of soft tissue sarcomas. A sarcoma is categorized by the tissue in which it has grown:

Malignant tumors in fat are called liposarcomas.
In smooth muscle around internal organs, cancerous sarcomas are known as leiomyosarcomas.
Rhabdomyosarcomas are malignant tumors in skeletal muscle. Skeletal muscle is located in your arms, legs, and other areas of the body. This type of muscle enables movement.
Gastrointestinal stromal tumors (GISTs) are malignancies that begin in the gastrointestinal (GI) tract, or digestive tract.

Other soft tissue sarcomas that are very rare include:

neurofibrosarcomas
malignant schwannomas
neurogenic sarcomas
synovial sarcoma
angiosarcomas
kaposis sarcoma
fibrosarcoma
malignant mesenchymomas
alveolar soft part sarcomas
epithelioid sarcomas
clear cell sarcomas
pleomorphic undifferentiated sarcomas
spindle cell tumors

Causes :

Usually, the cause of a soft tissue sarcoma isn’t identified.

The exception to this is Kaposi sarcoma. Kaposi sarcoma is a cancer of the lining of blood or lymph vessels. This cancer causes purple or brown lesions on the skin. It’s due to infection with the human herpes virus 8 (HHV-8). It frequently occurs in people with reduced immune function, such as those infected with HIV, but it can also arise without HIV infection.

Risk Factor:

Genetic risk factor

Some inherited or acquired DNA mutations, or defects, can make you more prone to developing a soft tissue sarcoma:

Basal cell nevus syndrome increases your risk of basal cell skim cancer, rhabdomyosarcoma, and fibrosarcoma.
Inherited retinoblastoma causes a kind of childhood eye cancer, but it can also increase the risk of other soft tissue sarcomas.
Li-Fraumeni syndrome increases the risk of many kinds of cancer, often from radiation exposure.
Gardner syndrome leads to cancers in the stomach or bowel.
Neurofibromatosis can cause nerve sheath tumors.
Tuberous sclerosis can result in rhabdomyosarcoma.
Werner’s syndrome can cause many health problems, including an increased risk of all soft tissue sarcomas.

Toxin exposure

Exposure to certain toxins, such as dioxin, vinyl chloride, arsenic, and herbicides that contain phenoxyacetic acid at high doses may increase risk of developing soft tissue sarcomas.

Radiation exposure

Radiation exposure, especially from radiation therapy can be a risk factor.

Symptoms

In its early stages, a soft tissue sarcoma may not cause any symptoms. A painless lump or mass under the skin of your arm or leg may be the first sign of a soft tissue sarcoma. If a soft tissue sarcoma develops in your stomach, it may not be discovered until it’s very large and pressing on other structures. You may have pain or breathing difficulties from a tumor pushing on your lungs.

Another possible symptom is an intestinal blockage. This can occur if a soft tissue tumor is growing in stomach. The tumor pushes too hard against intestines and prevents food from moving through easily. Other symptoms include blood in stool or vomit or black, tarry stools.

Diagnosis:

soft tissue sarcoma diagnosed mostly,when the tumor becomes large enough to be noticed because there are very few early symptoms. By the time the cancer causes recognizable signs, it may already have spread to other tissues and organs in the body.

Imaging techniques

Which includes mainly contrast enhanced MRI, PET scan.

Biopsy

Ultimately, a biopsy confirm the diagnosis.

Some other tests performed on a tumor sample from a biopsy include:

immunohistochemistry, which looks for antigens or sites on tumor cells to which certain antibodies can attach
cytogenic analysis, which looks for changes in the chromosomes of the tumor cells
fluorescence in situ hybridization (FISH), a test to look for certain genes or short pieces of DNA
flow cytometry, which is a test that looks at the number of cells, their health, and the presence of tumor markers on the surface of cells

Treatments :

Treatment depends on the location of the tumor and the exact cell type that the tumor originated from (for example, muscle, nerve, or fat). If the tumor has metastasized, or spread to other tissues, this also affects treatment.

Surgery

Surgical treatment is the most common initial therapy. Surgeon will remove the tumor and some of the surrounding healthy tissue and test to see if some tumor cells may still be left in body, also need to remove surrounding lymph nodes.

In the past, doctors would often need to amputate a limb that had tumors. Now, the use of advanced surgical techniques, radiation, and chemotherapy can often save a limb. However, large tumors that affect major blood vessels and nerves may still require limb amputation.

Chemotherapy

chemotherapy is also used to treat soft tissue sarcomas which are diagnosed ion advanced stage or metastatic(spreads to different parts of the body).

Radiation therapy

In radiation therapy, high-energy beams of particles such as X-rays or gamma rays damage the DNA of cells. Rapidly dividing cells such as tumor cells are much more likely to die from this exposure than normal cells, though some normal cells will die as well. It can be used along with chemotherapy.