Soft tissue sarcoma is a malignant tumour that starts in the cells of the connective and supporting tissues. Malignant means that it can spread, or metastasize, to other parts of the body.
There are many different types of soft tissue throughout the body, including fat, muscle, tendons, ligaments, blood vessels and more. Soft tissues have many functions, but mainly they support, protect and connect body tissues and structures.
Cells in soft tissue sometimes change and no longer grow or behave normally. These changes may lead to benign tumours such as a lipoma, which starts in fat cells, or a leiomyoma, which starts in smooth muscle cells. Benign tumours are not cancerous. But in some cases, changes to soft tissue cells can cause cancer.
Cancer that starts in soft tissue cells is called soft tissue sarcoma. Different types of sarcomas can start in different soft tissues. Because soft tissues are found throughout your body, soft tissue sarcomas can develop anywhere in your body. More than half of all soft tissue sarcomas develop in an arm or leg. The rest start in the chest, head and neck or abdomen.
Soft tissue sarcomas are different from bone cancers, which are also called sarcomas. Bone and cartilage are specialized types of connective tissues, but they are not soft tissues. Sarcomas of the bone behave differently and are treated differently than soft tissue sarcomas.