|
|
|
 |
|
| Detailed Guide: Sarcoma - Adult Soft Tissue Cancer |
What Is Sarcoma? |
|
Soft tissue sarcomas are malignant (cancerous) tumors that can develop from fat, muscle, nerve, joint, blood vessel, or deep skin tissues. They can develop in any part of the body. Half of them develop in the arms or legs. The rest arise in the trunk, head and neck area, internal organs, or the retroperitoneum (the back of the abdominal cavity).
The term soft tissue is used to distinguish these sarcomas from bone sarcomas. Bone sarcomas (osteosarcomas) are discussed in a different ACS document.
There are many types of soft tissue tumors, and not all of them are cancerous. When a tumor is not cancerous, it is called benign. When the term sarcoma appears in the name of a disease, it means the tumor is malignant.
Here is a list of common tumor types that can develop from different soft tissues.
Tumors of Fat Tissue
Lipomas are benign tumors of fat tissue. They are the most common benign soft tissue tumor. Most are found under the skin, but they can develop anywhere in the body. Lipoblastomas and hibernomas, like lipomas, are also benign fat tissue tumors.
Liposarcomas are malignant tumors of fat tissue. They can develop anywhere in the body, but they most often develop in the thigh and inside the back of the abdomen. This occurs mostly in adults between 50 and 65 years old. Some liposarcomas can be very slow growing, whereas others can grow quickly. Your doctor can tell you which kind you have.
Tumors of Muscle Tissue
The human body contains 2 types of muscle:
- One kind is smooth muscle, which is found in our internal organs such as stomach, intestines, blood vessels, or uterus (womb) and causes them to contract. These muscles are involuntary -- that is, we don't control their movement.
- The other kind is striated (striped as seen under the microscope) or skeletal muscle. This is the muscle that allows us to move our arms and legs and other body parts on purpose -- that is, voluntary movement.
Leiomyomas are benign tumors of the involuntary muscle (or smooth muscle). The most common of these is the "fibroid" tumor that develops in many women. It is really a leiomyoma of the uterus.
Leiomyosarcomas are malignant tumors of involuntary muscle tissue. They can grow almost anywhere in the body but are most often found in the retroperitoneum and the internal organs where leiomyomas also arise. Less often, they develop in the deep soft tissues of the legs or arms.
Rhabdomyomas are benign tumors of skeletal muscle (the muscle that is attached to bone and helps us to move).
Rhabdomyosarcomas are malignant tumors of skeletal muscle. These tumors commonly grow in the arms or legs, but they can also begin in the head and neck area and in reproductive and urinary organs such as the vagina or bladder. Children are affected much more often than adults. For more information, see our document on Rhabdomyosarcoma.
Tumors of Peripheral Nerve Tissue
Nerves run throughout the body. The brain and spinal cord are also considered central nerve tissue. The tumors discussed here are tumors of the nerves that run throughout the body, but not the brain or spinal cord.
Neurofibromas, schwannomas, and neuromas are all benign tumors of nerves.
Malignant schwannomas, neurofibrosarcomas, or neurogenic sarcomas are malignant tumors of the cells that surround a nerve. A new name for these is malignant peripheral nerve sheath tumors.
Ewing's tumors are a group of related cancers that include Ewing's sarcoma of bone, extraosseous (not in bone) Ewing's (EOE), and primitive neuroectodermal tumor (PNET). All of these cancers share some features with nerve tissue of a developing embryo. They are common in children but very rare in adults. For more information, see our document on Ewing's Family of Tumors.
Tumors of Joint Tissue
All our joints are surrounded by tough tissue called synovium, which produces the fluid that lubricates the joint surfaces so that they move smoothly. Tumors of joints start in the synovium.
Nodular tenosynovitis is a benign tumor of joint tissue. It is most common in the hands and is more common in women than in men.
Synovial sarcoma is a malignant tumor of the tissue around joints. The most common location is the knee. It tends to occur in young adults.
Tumors of Blood Vessels and Lymph Vessels
Hemangiomas are benign tumors of blood vessels. They are rather common, are often present at birth, and can affect the skin or internal organs. They sometimes disappear without treatment.
Lymphangiomas are benign lymph vessel tumors that are usually present at birth. Lymph is a type of fluid that circulates in every tissue of the body, ending up in the venous system. It contains waste products from tissues and immune system cells.
Angiosarcomas are malignant tumors that can develop either from blood vessels (hemangiosarcomas) or from lymph vessels (lymphangiosarcomas). These tumors can sometimes develop in a part of the body that has been exposed to radiation. These are sometimes seen in the breast after radiation therapy for breast cancer or in the arm on the same side as a breast that has been irradiated or removed by mastectomy.
Kaposi's sarcoma is a cancer formed by cells similar to those lining blood or lymph vessels. In the past, Kaposi's sarcoma was an uncommon cancer mostly seen in older people with no apparent immune system problems. It is most common in people with human immunodeficiency virus (HIV) infection and the acquired immunodeficiency syndrome (AIDS), but it can also develop in organ transplant patients who are taking medication to suppress their immune system. It is probably related to infection with a virus called human herpesvirus-8 (HHV-8). For more information, see our documents on Kaposi's Sarcoma and HIV/AIDS.
Hemangioendothelioma is a blood vessel tumor that is less aggressive than hemangiosarcoma but still considered a low-grade cancer. It usually invades nearby tissues and sometimes can spread to distant parts of the body (metastasize). It may develop in soft tissues or in internal organs, such as the liver or lungs.
Tumor of Perivascular Tissue
The term perivascular means around the blood vessels. Normal perivascular cells help control the amount of blood flowing through blood vessels.
Glomus tumors are benign perivascular tumors. They usually are found under the skin of the fingers.
Hemangiopericytoma is a sarcoma of perivascular tissue. It most often develops in the legs, pelvis, and retroperitoneum (the back of the abdominal cavity). It is most common in adults.
Tumors of Fibrous Tissue
Fibrous tissue forms tendons and ligaments.
Fibromas, elastofibromas, superficial fibromatosis, and fibrous histiocytomas are all benign tumors.
Fibrosarcoma is cancer of fibrous tissue. It usually affects the legs, arms, or trunk. It is most common between the ages of 30 and 55.
Desmoid tumor, also called aggressive fibromatosis, is a fibrous tissue tumor with features in between fibrosarcoma and benign tumors such as fibromas and superficial fibromatosis. Desmoids do not metastasize, but they can invade nearby tissues and are sometimes fatal. Some doctors consider desmoids to be a type of low-grade fibrosarcoma; others believe they are a unique type of fibrous tissue tumors. Certain hormones, particularly estrogen, increase the growth of some desmoid tumors. Antiestrogen drugs are sometimes useful in treating desmoids that cannot be completely removed by surgery.
Dermatofibrosarcoma protuberans (DFSP) is a low-grade cancer of the fibrous tissue beneath the skin, usually in the trunk or limbs. It invades nearby tissues but rarely metastasizes.
Malignant fibrous histiocytoma (MFH) is the most common malignant soft tissue tumor found in the arms or legs. Less often, it can develop inside the back of the abdomen. This sarcoma is most common in older adults.
Tumors of Uncertain Tissue Type
Through microscopic examination and other laboratory tests, doctors can usually find similarities between most sarcomas and certain types of normal soft tissues. However, some sarcomas have not been linked to a specific type of normal soft tissue.
Myxoma is a benign tumor that usually is located in muscles but does not develop from muscle cells. The cells of a myxoma produce mucus-like material, a feature that distinguishes this tumor.
Malignant mesenchymoma is a rare type of sarcoma that contains some areas showing features of fibrosarcoma and other areas with features of at least two other types of sarcoma.
Alveolar soft-part sarcoma is a rare cancer that mostly affects young adults. The legs are the most common location of these tumors.
Epithelioid sarcoma most often develops in tissues under the skin of the hands, forearms, feet, or lower legs. Adolescents and young adults are often affected.
Clear cell sarcoma is a rare cancer that often develops in tendons and related tissues. Under the microscope, it shares some features with malignant melanoma, a type of cancer that develops from pigment-producing skin cells. How cancers with these features develop in parts of the body far from the skin is not known.
Desmoplastic small cell tumor is a rare sarcoma of adolescents and young adults, found most often in the abdomen. Its name means that it is formed by small, round cancer cells surrounded by scar-like tissue.
Tumor-like Conditions of Soft Tissue
Some conditions of soft tissues are caused by inflammation or injury and can form a mass that looks like a soft tissue tumor. Unlike a true tumor, they do not come from a single abnormal cell, have limited capacity to grow or spread to nearby tissues, and never spread through the bloodstream or lymph system. Examples include nodular fasciitis and myositis ossificans, which involve tissues under the skin and muscle tissues, respectively.
|
|
|
|
|
