Types of Soft Tissue Sarcoma

Although soft tissue sarcoma is a relatively rare form of cancer, doctors have identified many different types. At The University of Kansas Cancer Center, we specialize in treating all forms of soft-tissue cancer.

Malignant fibrous histiocytoma: Soft tissue tumor

Malignant fibrous histiocytoma is the most common type of soft tissue sarcoma. It originates in fibrous tissue, the tough tissue that forms tendons and ligaments, and covers bones and other parts of the body. MFH can also spread to the bones.

MFH typically affects adults between ages 50 to 70, and is more common in men and Caucasians. The most common location for the tumor to occur is the thigh, followed by the arm and abdomen. A milder form of MFH involves the skin and is known as a cutaneous MFH.

Malignant fibrous histiocytoma is a painless soft tissue mass that slowly increases in size until it starts causing symptoms like swelling, pain, numbness and tingling. The mass can invade bone and cause fractures. In most cases, the tumor has been growing for 4 to 6 months by the time a patient visits a doctor.

MFH is an aggressive soft tissue cancer that is likely to recur and spread (metastasize) to the lungs, lymph nodes, liver and bone.

Leiomyosarcoma: Malignant soft tissue tumor

Leiomyosarcoma is the 2^nd most common soft tissue sarcoma occurring in adulthood. It accounts for up to 25% of all soft tissue sarcomas. Leiomyosarcoma typically appears as a slowly enlarging, painless soft tissue mass that occurs deep in the soft tissues of the extremities.

These malignant tumors affect men more than women, typically around age 50. They are uncommon in children. Leiomyosarcomas arise from smooth muscles, which are muscles that are not voluntarily controlled, such as the muscle that causes the hair on the arms to stand on end. These tumors often grow within the walls of the veins or intestines. Most people have no symptoms until the tumor is large enough to affect nearby areas, causing tenderness, pain or decreased range of motion. It is not uncommon for leiomyosarcomas to grow larger than cantaloupes or even watermelons.

Liposarcoma: Malignant soft tissue tumor

Liposarcoma is another of the more common soft tissue sarcomas occurring in adulthood. It accounts for up to 25% of all soft tissue sarcomas. Liposarcoma usually develops deep within the musculature, with the thigh being the most typical location. Most patients with liposarcoma have no symptoms until the tumor is large and impacts neighboring areas.

These tumors occur in men more often than women, typically between ages 40 to 60. Often, liposarcomas have no symptoms when the tumor is still small. Tumor growth can cause later symptoms such as painful swelling, decreased range of motion, numbness, enlargement of varicose veins, fatigue, nausea, vomiting or weight loss.

Five-year survival is 100% for cases of liposarcoma where the cancer cells look more like normal tissue. This is known as a well-differentiated tumor. The area where the tumor is located has a major impact in survivorship rates.

Angiosarcoma: Malignant soft tissue tumor

Angiosarcoma is a cancer of the inner lining of blood vessels that can occur in any area of the body. The disease most commonly occurs in the skin, breast, liver, spleen and deep tissues, as well as the scalp. Angiosarcomas are rare, accounting for only 1% of all soft tissue sarcomas.

Like other soft tissue cancers, angiosarcomas exhibit little to no pain or other symptoms. Angiosarcomas often spread along the skin and to the lungs before a patient visits a doctor. These tumors often occur in areas of prior radiation.

Up to 50% of those with angiosarcoma may have distant spread of the disease at the time of diagnosis, which may shorten survival. Overall survival depends on the state and aggressiveness of disease. Many people can live 5 years or more.

Retroperitoneal Sarcoma

Retroperitoneal sarcoma occurs in the retroperitoneum, the space between the peritoneum and the posterior abdominal wall. The retroperitoneal space contains the kidneys, adrenal glands, pancreas, nerve roots, lymph nodes, abdominal aorta and inferior vena cava.

Between 15%-20% of soft tissue sarcomas develop in the retroperitoneum. One-third of malignant tumors that occur in the retroperitoneum are sarcomas. Soft tissue sarcomas are rare, with approximately 13,000 new cases diagnosed each year in the United States ‒ less than 1% of all cancer diagnoses.

Because retroperitoneal sarcomas are rare, and frequently not discovered until they are advanced (5cm or greater), evaluation and treatment can be challenging. Additionally, these tumors occur in an anatomically complex location. Retroperitoneal sarcomas include:

• Well-differentiated liposarcoma, the most common type of liposarcoma, is a slow growing, painless tumor that can start anywhere in the body but most commonly arises in the abdomen. Well-differentiated liposarcoma and dedifferentiated liposarcoma are closely related.
• Dedifferentiated liposarcoma is a fast-growing, painless tumor that progresses from well-differentiated liposarcoma and most often occurs in the abdomen. Symptoms may include abdominal distention, decreased appetite and obstruction.
• Solitary fibrous tumors may or may not be cancer. Some start in the thigh, underarm and pelvis. They can also start in the pleura, the tissue surrounding the lung.
• Leiomyosarcoma is a type of soft tissue sarcoma that can develop in soft tissues like fat, muscle, nerves, fibrous tissues, blood vessels or deep skin tissues. Leiomyosarcoma can be found in any part of the body, including reproductive organs like the uterus. Uterine leiomyosarcoma starts in the muscular wall of the uterus and can grow and spread quickly.
• Gastrointestinal stromal tumor (GIST) is a type of sarcoma that starts in the digestive tract. Most GISTs occur randomly and have no clear cause. Some GISTS develop as a result of genetic changes, which researchers are studying. There are no known lifestyle-related or environmental risk factors for GIST.
• Desmoid tumor (also known as fibromatosis) is a type of intermediate soft tissue sarcoma. Describing a soft tissue tumor as intermediate does not mean it is benign, or not cancer. Rather, intermediate soft tissue sarcomas behave in ways between a cancer and a non-cancer.
• Myxoid-round cell liposarcoma is a type of liposarcoma, a rare cancer that grows in the body’s fat-storing cells. MRCLS usually grow slowly in the arms and legs but can spread to other parts of the body.
• Pleomorphic liposarcoma is a malignant tumor that usually arises from fat in the body and is commonly found in the abdomen. Pleomorphic liposarcoma represents approximately 5% -10% of all liposarcomas. It is the least common but most aggressive subtype of liposarcoma.