Soft tissue sarcoma in the extremities and trunk wall consists of many subtypes with some common features
but with differences in biological behavior.
The types occurring most often are:
- liposarcoma - malignant tumor with fat differentiation
- pleomorphic and spindle cell sarcoma/malignant fibrous histiocytoma (MFH) - poorly differentiated sarcoma
- leiosarcoma - malignant tumor with smooth muscle cell differentiation
- synovial sarcoma - malignant tumor with spindle-formed and epitheloid cells
Other types which occur less frequently are angiosarcoma, spindel cell sarcoma (Ewing's sarcoma/PNET, rhabdomyosarcoma, small cell round cell desmoplastic tumor, mesenchymal chondrosarcoma), malignant perpheral nerve tumor (MPNST), fibrosarcoma, and solitary fibrous tumor/hemangiopercytoma.
Soft tissue sarcoma can occur anywhere in the body, but the most common location is the lower extremities which constitute 45% of cases.
Among all soft tissue sarcomas, 60% are located in the extremities, abdominal and thoracic wall, 20% abdominal/retroperitoneum, and 20% in the head/neck or internal genitals in women.
Soft tissue sarcoma occurs in all age groups. The average age is about 60 years. The disease occurs more frequently in men than women. Synovial sarcoma occurs most often in youth and young adults while rhabdomyosarcoma occurs most frequently in children. In 2015, 312 persones were diagnosed with soft tissue sarcoma in Norway, 143 men and 169 women.