What is Cancer?
Cancer is the general name for a group of over 100 diseases in which cells in a part of the body become abnormal and divide uncontrollably. A tumor, or malignant growth, is the result of this mass division of cells. Cancer is formed when healthy cells mutate turning normal cells into abnormal, and the abnormality allows those cells to multiply rapidly and not die off as they should.
What is a Soft Tissue Sarcoma?
A sarcoma is a less common form of cancer that develops from specific tissues such as bone or muscle. Soft tissue sarcomas may develop from tissues including fat, muscle, nerve, blood vessels, deep skin or fibrous tissues. These sarcomas may be found anywhere in the body, though most develop in the arms, hands, or legs.
There are several types of soft tissue tumors, though not all are cancerous (malignant) as some are classified as non-cancerous (benign). When referencing sarcoma as part of a disease it is typically referring to a malignant tumor. This page will focus on soft tissue tumors and sarcomas, and will break down which tumors are generally classified as benign or malignant.
What Causes Soft Tissue Sarcomas?
Malignant soft tissue sarcoma is a rare cancer that occurs in less than 15,000 new cases each year in the US. The cause, as with many cancers, is not well known. Kaposi sarcoma, listed below, tends to occur in people with weak or defective immune systems such as the elderly or people with HIV, and is caused by a virus called human herpes virus 8 (HHV-8). It is long suspected that radiation exposure or chemical exposure could increase your risk of developing a soft tissue sarcoma.
Other sarcomas may be hereditary and developed from such conditions as:
- Basal cell nevus syndrome
- Inherited retinoblastoma
- Tuberous sclerosis
- Werner's syndrome
- Gardner's syndrome
- Li-Fraumeni syndrome
Types of Soft Tissue Sarcoma:
There are over fifty variable soft tissue sarcomas, either benign or malignant, though most are extremely uncommon. Very brief overviews of the types that are most readily seen and documented include:
Fat Tissue Tumors
- Lipomas - benign, a common tumor that develops under the skin but can be located throughout the body, and is the most common benign soft tissue tumor.
- Lipoblastomas - benign, occurring in children and infants.
- Hibernomas - benign, less common fat tissue tumors.
- Liposarcoma - malignant, can develop throughout the body though most commonly found in the knee bend or back of the abdomen, typically developing in adults over the age of 50.
Muscle Tissue Tumors
- Rhabdomyomas - benign, found in skeletal muscle and quite rare.
- Leiomyomas - benign, found in smooth muscle and can be found anywhere in the body as these tumors develop from the walls of the blood vessels. While they are found in both men and women, they are most commonly found in the walls of the uterus, with a common name of fibroids.
- Leiomyosarcoma - malignant, found in smooth muscle throughout the body though most commonly in the back of the abdominal cavity, occurring primarily in adults and the elderly.
- Rhabdomyosarcoma - malignant, found in skeletal muscle most often in the arms or legs affecting more children than adults.
Fibrous Tissue Tumors
- Fibromas - benign.
- Fibrous histiocytomas – benign.
- Superficial fibromatosis – benign.
- Elastofibromas – benign.
- Fibromatosis - low-grade malignant potential, fibrous tissue tumors that show features of fibrosarcoma and benign fibromas. These tumors grow slowly and tend to not spread far within the body. While not all are malignant, they can still be fatal. Estrogen affects these tumors negatively and can cause them to grow at a faster rate.
- Dermatofibrosarcoma protuberan - slow-growing malignant, found beneath the skin.
- Fibrosarcoma - malignant, affecting the arms and legs primarily and most common in adults.
Peripheral Nerve Tissue Tumor
- Gatrointestinal stromal tumor (GIST) - malignant, develops in the cells of the digestive tract that control the muscles within the stomach and intestine.
Joint Tissue Tumors
- Nodular tenosynovitis - benign, found primarily in the hands and more often in woman.
- Synovial sarcoma - malignant, most commonly found in children and young adults in the ankle, knee, shoulder, or hip.
Blood and Lymph Vessels Tumors
- Hemangiomas - benign, quite common tumors that affect internal organs or skin and often present at birth.
- Lymphangiomas - benign, typically present at birth these tumors are made from lymph which is a type of fluid that circulates throughout tissues in the body carrying waste products from the immune system cells.
- Glomus tumors - benign, generally found in the fingers and developing under the skin.
- Hemangiopericytoma - benign or malignant, a tumor of the perivascular tissue that typically begins in the pelvis or leg and rarely spreads.
- Hemangioendothelioma - low-grade cancer, this tumor is slow growing and often grows into nearby tissues or internal organs.
- Kaposi sarcoma - malignant, formed from cells similar to blood or lymph vessels, found most often in adults with suppressed immune systems such as HIV or organ transplant patients, though also found in the elderly.
- Angiosarcoma - malignant, these tumors are linked to radiation exposure and often found in areas of the body previously exposed to radiation therapy.
Uncertain Tissue Type Tumors
- Granular cell tumor - benign, found primarily in adults and occurring most often in the tongue.
- Myxoma - benign, located in the muscles but is not formed from muscle tissue. The cells produce a mucas-like substance that distinguishes this tumor from others.
- PEComa - benign, a group of tumors consisting of abnormal cells called Perivascular Epithelial Cells, the most common of which are angiomyolipoma and lymphangioleiomyomatisis affecting the kidney and lung respectfully.
- Alveolar soft-part sarcoma - malignant, rare cancer found primarily in young adults and occurring more commonly in the legs.
- Malignant mesenchymoma - malignant, a rare cancer that often presents as two forms of sarcoma including fibrosarcoma as one of the two.
- Epithelioid Sarcoma - malignant, is the most common soft-tissue sarcoma in the hand, which is more common in young adults and children. It is a slow growing cancerous soft tissue tumor that generally poses minimal symptoms as a warning sign. Once formed, the sarcoma may attach itself to the surrounding tendons or joint capsule before then spreading further.
- Desmoplastic small round cell tumor - malignant, rare sarcoma found primarily in the abdomen of young adults.
- Clear cell sarcoma - malignant, rare cancer in the tendons found in the arms or legs that develops from pigment-producing skin cells.
- Pleomorphic undifferentiated sarcoma - malignant, most often found in the arms or legs, more common in adults.
- Spindle cell tumor - malignant.
Symptoms of Soft Tissue Sarcomas:
Because there are so many different subtypes of soft tissue sarcomas, the symptoms will vary. Below is a list of the most common symptoms and signs based on the location of the sarcoma.
- Shortness of breath (lung)
- Excessive chronic cough (lung)
- Abdominal pain (abdomen, abdominal organs)
- Vaginal bleeding or excessive pain (uterus)
- Lump beneath the skin surface
- Lump that returns after surgical removal
- Lump found deep in the skin tissue
Diagnosis of Soft Tissue Sarcomas:
Soft tissue sarcomas are often hard to diagnose, as the symptoms are often mild as well as shared with many other conditions. Typically, if a sarcoma is suspected a physical exam will occur followed by additional tests of the problem area. Blood test may be run, x rays may be taken, and in the case of a lump a biopsy may be performed.
If a sarcoma is suspected, but cannot be easily identified through a physical exam, imaging scans may be performed to gather additional information. These include:
- MRI scan
- CT scan
- PET scan
Once a cancer is diagnosed, it is then graded and staged to help determine the best treatment options for the best end result. Grading refers to the appearance of the cancer cells when examined under a microscope, and the stage refers to the size and spread of the cancerous cells.
Soft Tissue Sarcoma Grading:
Low grade: typical normal looking cancer cells, often slow growing and not as likely to spread.
Moderate grade: slightly abnormal cancer cells that grow at a moderate pace but not likely to spread very far.
High grade: abnormal cancer cells that tend to grow rapidly and may spread at a similar pace.
Soft Tissue Sarcoma Staging:
Stage I: low or moderate grade soft tissue cancers are found but have not spread to the lymph nodes or any major organs. At this stage the cancer is typically found near the surface of the body.
Stage II: the soft tissue cancer has not spread to the lymph nodes or any major organs, but is a moderate grade and deep within the body.
Stage III: soft tissue cancer is found deep within the body and is considered high grade, though has not begun to spread far.
Stage IV: any grade of soft tissue cancer of any size that is found near the surface or deep within the body, but has begun to spread to lymph nodes and other areas of the body including major organs.
Treatment for Soft Tissue Sarcomas:
Many sarcomas are treated via removal of the tumor, including limb sparing surgeries (which remove a portion of the limb versus a full amputation) to reduce the possibility of the cancer spread. Chemotherapy is often used alongside radiation therapy, in addition to surgery.
Additional Resources for Soft Tissue Sarcomas:
National Cancer Institute coordinates the National Cancer Program, which conducts and supports research, training, health information dissemination, and other programs with respect to the cause, diagnosis, prevention, and treatment of cancer, rehabilitation from cancer, and the continuing care of cancer patients and the families of cancer patients.
Memorial Sloan-Kettering Cancer Center provides information on soft tissue sarcoma and access to innovative therapies through clinical trials.
MD Anderson Cancer Center has a dedicated medical staff for treating and researching soft tissue sarcoma.
Macmillan Cancer Support UK offers information about a variety of cancers including soft tissue sarcomas.