X-ray - knee joint with large osteolytic lesion of the medial aspect of the left distal femur with soft tissue and malignant bone tumor, suspected osteosarcoma. (Source: Shutterstock)
Soft Tissue Sarcoma
Soft Tissue Sarcomas are malignant tumours which arise from the soft tissue of the body – also in the connective tissue and muscle. It is a relatively rare form of cancer, although more commonly found in children and adolescents than other age groups. Currently on average two new people per 100,000 develop a soft tissue sarcoma each year.
Sarcomas are classified by the tissue that they emerge from: adipose (fat) tissue, connective tissue, vessels, tendons, joint capsules, muscles or musculocutaneous nerve. The lower extremities are typical location for a soft part sarcoma. Around 60 percent of all sarcoma tumours can be found in the arms or legs, one-third arise in the torso, and occasionally they can be found in the neck and face area.
Numerous risk factors for the development of a soft tissue sarcoma have been described, but they explain only a fraction of the sarcomas. Chemical carcinogens can play a role in their formation. Soft tissue sarcomas are often found in the context of genetic diseases, and to a lesser extent, a familial predisposition.
For the formation of Kaposi, the Human herpes virus (HHV) 8 is responsible. This works fastest in an immunocompromised organism (patients with HIV-1).
A frequent occurrence of tissue injury on random parts of the body is observable. Sarcomas can often be found around operation or burn scars, and previous tissue transplants. In addition there is a significant association with radiation, such as radio-therapy or radioactive exposure.
Space-occupying tumours can be detected depending on the location. Patients often complain about pain in the affected regions. This includes a local pressure or tensile feeling. But also neurological complaints by trapped nerves and circulatory disorders by vascular compression can occur.
Basically with any new mass, unless it is an absolutely non-malignant origin, a biopsy should be carried out. Sarcomas are diagnosed by X-ray, computed tomography, and magnetic resonance imaging. For the differential diagnosis, is always a biopsy required.