summary Angiosarcomas are malignant, aggressive tumors that derive from the endothelium of blood vessels. The condition is typically seen in elderly patients who present with regional pain and overlying skin changes. Diagnosis is made with a biopsy showing malignant cells associated with vascular structures. Treatment is usually wide surgical resection with radiation. Epidemiology Demographics male > female elderly Anatomic location osseous involvement in <10% 60% long bone with osseous involvement Risk factors chronic vascular stasis trauma exposure to polyvinyl chloride Symptoms Symptoms pain symptoms often insidious Physical exam hallmarked with overlying skin changes Imaging Radiograph may see the invasion of bone MRI study of choice to evaluate soft tissue mass Studies Histology vascular channels variable degree of anaplasia malignant cells associated with vascular structures CD31 endothelial marker positive Treatment Operative wide surgical resection indications treatment of choice relatively insensitive to chemotherapy and radiation amputation indications to achieve local control of disease very aggressive tumor Prognosis Poor prognosis high local failure rate and amputation is often required propensity for lymphatic spread metastases to lung is common