Skin fibrosarcoma. Excised specimen of a skin tumour known as a fibrosarcoma. For its protruding nature, the full medical name of this cancer is dermatofibrosarcoma protruberans. The tumour has been sliced open (white). The scale reference is in centimetres. A fibrosarcoma is a rare malignant cancer of the cells that make up connective tissue. It most often develops around muscles in a limb; here it is close to the skin surface. Fibrosarcoma causes a localized swelling which may be warm to the touch and may pulsate. Its spread to other parts of the body via the bloodstream may be rapid. Early treatment is most successful, by surgical removal and/or radiotherapy.