Sarcoma, Soft Tissue

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Sarcoma, Soft Tissue: Overview

Approved by the Cancer.Net Editorial Board, 08/2017


Cancer begins when healthy cells change and grow out of control, forming a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread.

About sarcoma

Sarcoma can start in any part of the body, such as the bone or soft tissue.

  • 60% begin in an arm or leg
  • 30% start in the torso or abdomen
  • 10% occur in the head or neck

Both children and adults can develop a sarcoma. It is rare in adults, accounting for about 1% of all adult cancers. However, sarcomas are more common in children, representing about 15% of all childhood cancers.

This section covers sarcoma of the soft tissues. Learn more about sarcoma that starts in a bone.

About soft-tissue sarcoma

Soft-tissue sarcoma (STS) is a group of cancers that begin in the connective tissues that support and connect the body, including:

  • Blood vessels
  • Fat cells
  • Lining of joints
  • Lymph vessels
  • Muscle
  • Nerves
  • Tendons

As a result, STS can occur almost anywhere in the body. When an STS begins and is small, it can go unnoticed because it usually does not cause problems. However, as an STS grows, it can interfere with the body’s normal functions.

Because there are more than 50 different types of STS, it is more accurate to describe them as a family of related diseases rather than as a single disease. Specific types of sarcoma are often named according to the normal tissue cells they most closely resemble, as listed below. This is different from most other types of cancer, which usually are named for the part of the body where the cancer began. Some sarcomas do not look like any type of normal tissue and are thought to come from stem cells or other primitive cells. Stem cells are special cells that can mature into specific tissues or organs.

The list below describes several common types of STS and related connective tissue tumors.


Name of Sarcoma Related Normal Tissue Type
Angiosarcoma Blood or lymph vessels
Desmoid tumor, also called deep fibromatosis Fibroblasts, which are the most common type of cells in connective tissue
Ewing family of tumors No obvious related normal tissue; may be a tumor of stem cells
Fibrosarcoma Fibroblasts, which are the most common type of cells in connective tissue
Gastrointestinal stromal tumor (GIST) Specialized neuromuscular cells of the digestive tract
Kaposi sarcoma Blood vessels
Leiomyosarcoma Smooth muscle
Liposarcoma Fat tissue
Myxofibrosarcoma Connective tissue
Malignant peripheral nerve sheath tumor (MPNST), also known as neurofibrosarcoma Cells that wrap around nerve endings, similar to the way insulation wraps around a wire
Rhabdomyosarcoma Skeletal muscle
Synovial sarcoma No obvious related normal tissue; may be a tumor of stem cells
Undifferentiated pleomorphic sarcoma (UPS), often referred to as malignant fibrous histiocytoma (MFH) in the past No obvious related normal tissue; may be a tumor of stem cells or a distant relative of rhabdomyosarcoma

Expert pathologists have described and classified many types and subtypes of sarcomas. A pathologist is a doctor who uses a microscope to look at the tumor specimen to make the diagnosis. Pathologists are looking for new ways to quickly determine a tumor’s subtype because this helps the health care team understand the prognosis and decide on the treatment plan. Looking at a tumor’s abnormal genetics may help determine its characteristics and predict which treatments will be most effective. The use of targeted therapy has resulted in major advances in treating several types of sarcoma, including GIST, dermatofibrosarcoma protuberans (DFSP), tenosynovial giant cell tumor, and desmoid tumors.

Pathologists also describe sarcoma by its “grade,” which describes how closely cancer cells look or don’t look like healthy cells when viewed under a microscope. A higher-grade tumor has cells that look more abnormal and are potentially more aggressive. The grade can help the doctor predict how quickly the sarcoma will grow and spread. In general, the lower the tumor’s grade, the less the likelihood it will recur and/or spread. Learn more about grade in the Stages and Grades section.

Read more about Sarcoma, Soft Tissue here.

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