What is angiosarcoma?

• Malignant neoplasm showing morphological or immunophenotypic evidence of endothelial differentiation • Skin (H&N), soft tissues, breast (Primary/2nd), liver • Wide morphologic appearance: Well-differentiated to anaplastic • Metastasize rapidly. 5ys 30%. • Irregularly shaped anastomosing vascular channels or sheet-like growth • Highly infiltrative architecture and poor demarcation • Multilayering of endothelial cells, nuclear atypia, increased mitoses, necrosis Positive for vascular markers, such as CD31, CD34, ERG, VEGF and factor VIII, by IHC