Types of soft tissue sarcoma
A soft tissue sarcoma is cancer. This means that it can spread (metastasize) to other parts of the body. Soft tissue sarcomas start in mesenchymal cells, which are the basic cells that develop into different types of soft tissue. These tumours are sometimes called mesenchymal tumours.
Soft tissue sarcoma is not a common cancer. Some types are more common in children, and others are more common in adults. Certain types of soft tissue sarcoma occur more often in a specific age group. Some types occur in certain parts of the body:
- Over 50% of soft tissue sarcomas begin in the limbs. They develop in lower limbs more often than upper limbs and occur most often in the thigh.
- About 15% of soft tissue sarcomas start inside the abdomen or chest.
- About 15% of soft tissue sarcomas start in the retroperitoneum (back of the abdominal cavity).
- About 5-10% occur in the head or neck.
There are over 50 different types of soft tissue sarcoma. They are named based on the type of normal soft tissue cells the cancer cells look like under a microscope. The most common soft tissue sarcomas are:
Fat tissue tumours
Liposarcoma is a cancerous soft tissue tumour that starts in the fatty (adipose) tissue of the body.
Fibrous tissue tumours
Several different cancerous tumours can develop in fibrous tissues that join together the inner structures of the body. Some soft tissue sarcomas of the fibrous tissue include:
- malignant fibrous histiocytomas
- dermatofibrosarcoma protuberans
Muscle tissue tumours
Soft tissue sarcomas occur most often in smooth (involuntary) muscle. They may also develop in skeletal (voluntary) muscle.
Leiomyosarcoma develops in smooth muscle.
Rhabdomyosarcoma develops in skeletal muscle.
Blood and lymph vessel tumours
Cancerous tumours of the blood and lymphatic vessels may also be called malignant vascular tumours. These include:
- Kaposi sarcoma
Gastrointestinal stromal tumours (GISTS)
Gastrointestinal stromal tumours (GISTS) are a type of soft tissue sarcoma that can develop anywhere along the gastrointestinal tract.
Nerve tissue tumours
Cancerous tumours can develop anywhere along the peripheral nervous system (nerves outside the brain and spinal cord). These tumours include:
- malignant peripheral nerve sheath tumours
- malignant granular cell tumour
Extraskeletal tumours of bone and cartilage
Cancerous tumours made up of bone and cartilage tissue can develop outside of the bone. These tumours are described as extraskeletal. They are rare and include:
- extraskeletal osteosarcoma
- extraskeletal chondrosarcoma
Tumours of uncertain tissue type
Tumours are usually named and grouped based on the type of normal cells the cancer cells look like under a microscope. Many soft tissue sarcomas contain different types of cells. Some sarcomas are made of cells that do not look like any type of cell found in normal tissues. These tumours often have more immature cells, which haven’t developed into specialized cells that do certain jobs. This means that it may be difficult to tell what type of cell they started in. These include:
- alveolar soft-part sarcoma
- clear cell sarcoma
- desmoplastic small round cell tumour
- epithelioid sarcoma
- extraskeletal myxoid chondrosarcoma
- primitive neuroectodermal tumour (PNET)/extraskeletal Ewing tumour
- malignant mesenchymoma
- malignant PEComa
- spindle cell tumour and spindle cell sarcoma
- synovial sarcoma