Types of Soft Tissue Sarcomas
There are more than 50 types of soft tissue sarcomas. These cancers develop in the soft tissues of the musculoskeletal system. This includes muscle, cartilage, connective tissue, fat, nerves, and blood and lymph vessels.
As a group, soft tissue sarcomas are relatively rare cancers in the United States. Adult soft tissue sarcomas account for about 1% of cancer cases in this group. However, soft tissue sarcomas make up about 15% of cancer cases in children. Here’s a soft tissue sarcoma list that includes many of the more well-known ones.
Angiosarcomas are vascular sarcomas. When the cancer starts in blood vessels, it’s hemangiosarcoma. If the cancer is in lymph vessels, it’s lymphangiosarcoma. These sarcomas can affect any area of the body, but are more common in the skin on the head and neck. They can also develop in deep organs, such as the liver, and in areas previously treated with radiation therapy, such as the breast.
Desmoid tumors start in fibroblasts—the most common cells in connective tissue. Desmoid tumors have characteristics that put them somewhere between fibrosarcomas (see below) and benign connective tissue tumors. They typically grow slowly and rarely spread to distant sites or are fatal. However, they can still cause significant problems, because they invade nearby tissues and structures. Fibromatosis is another name for this type of soft tissue sarcoma.
Epithelioid sarcomas are also slow-growing. However, these soft tissue sarcomas often spread and recur. They typically develop as a firm, painless lump on a finger, hand, forearm, lower leg, or foot. Often, people don’t seek care right away for a single lump that isn’t causing pain. So, it’s common to have multiple lumps at the time of diagnosis. This soft tissue sarcoma most commonly affects teenagers and young adults.
Like desmoid tumors, fibrosarcomas develop in fibroblasts in the fibrous connective tissues at the ends of bones. Fibrosarcoma commonly affects the arms, legs and trunk. The infantile or congenital form of the cancer tends to be less aggressive than the adult form. The infantile form is the most common soft tissue tumor in children younger than 1 year of age. The adult form most often affects people between the ages of 20 and 60 years. However, older children—ages 10 to 15—can develop the adult form as well.
GISTs affect the digestive tract, most commonly the stomach or small intestine. They arise in specialized neuromuscular cells that control the muscular contractions of digestion. Most GISTs occur in people between the ages of 50 and 70 years. These tumors are rare in younger people.
Kaposi sarcoma is another one of the vascular sarcomas. It develops in the lining of either blood or lymph vessels. The tumors produce purplish lesions on the skin and mucous membranes. Kaposi sarcoma is closely linked to having a weakened immune system. In the United States, the main risk factor for developing it is having HIV (human immunodeficiency virus) infection. When an HIV-positive person develops Kaposi sarcoma, the person officially has AIDS. Among those not infected with HIV, Kaposi sarcoma can also affect organ transplant patients and people with certain European and Mediterranean heritage.
Leiomyosarcoma is one of the smooth muscle sarcomas. These cancers most often start in the abdomen, including in the uterus. When they affect the uterus, it is easy to mistake them for fibroids. Only a biopsy can tell the difference between a benign fibroid and a leiomyosarcoma. This type of sarcoma can also affect the smooth muscles in blood vessel walls, especially the large vessels in the abdomen and chest. This includes the inferior vena cava and the pulmonary artery.
Liposarcomas are cancerous fat cells. This rare form of sarcoma most often affects the abdomen, thigh, or area behind the knee. However, liposarcomas can develop anywhere. While liposarcomas can happen to people of all ages, older adults have the highest risk. Most people are between the ages of 50 and 65 years at diagnosis.
These cancers develop in the sheath—or covering—that surrounds peripheral nerve fibers. Peripheral nerves are the ones that run from the central nervous system—brain and spinal cord—throughout the body. They can affect any body part, but most often develop in the arms, legs and trunk. They often cause pain and weakness in the affected area. Other names for these tumors include neurofibrosarcomas, malignant schwannomas, and neurogenic sarcomas.
This type of soft tissue sarcoma develops in the connective tissue that surrounds muscles and separates muscles from skin. The tumors typically show up just under the skin in older people between 50 and 70 years of age. Sometimes, the tumors are located deeper within muscle groups. The limbs are the most common site for myxofibrosarcoma.
Rhabdomyosarcoma is the most common soft tissue sarcoma in children. It arises in primitive embryonic tissue destined to become skeletal muscle. These tumors can arise in nearly any structure or body cavity—most often in the head, neck, arms and legs. Sometimes, it affects organs in the urinary and reproductive system, such as the bladder, prostate gland, or uterus. Most patients are 10 years of age and younger. When it affects adults, it tends to be harder to treat.
Synovial sarcomas develop in tissue near or around joints. These tumors tend to affect larger joints, such as the shoulder, hip, knee and ankle. However, synovial sarcoma can happen anywhere, including the neck. This form of sarcoma is rare and slow-growing. It most often strikes teenagers and young adults between 15 and 40 years of age.
UPS is a rare form of soft tissue sarcoma. Undifferentiated means the cancer cells don’t look like the normal cells from which they develop. Pleomorphic means the cancer cells aren’t uniform, but have many shapes and sizes. UPS most often affects the arms and legs. It can also develop in a space called the retroperitoneum—the area of the abdomen behind the abdominal organs. Other names for UPS include malignant fibrous histiocytoma (MFH) and fibrohistiocytic sarcomas.
If you or a loved one received a diagnosis of a soft tissue sarcoma, talk with your doctor about the type of tumor and how it affects your treatment options.