It is an uncommon malignant tumor (less than 1% of primary liver malignancies). It is associated with cirrhosis in about one-third of the cases. Many patients have been exposed to polyvinyl chloride or to Thorotrast as a a radiographic contrast agent.
Cytologic diagnostic features
- Elongated cells, isolated or in tightly cohesive clusters and syncitia (well-differentiated tumors)
- Large, spindle or epithelioid cells, pleomorphic nuclei, multinucleated giant cells (poorly differentiated tumors)
- Abundant finely or coarsely vacuolated cytoplasm
- Anastomosing vascular pattern (cell block sections)
- Epithelioid hemangioendothelioma
- Other malignant tumors
Angiosarcoma cells are larger, more atypical and more monomorphous than those of epithelioid hemangioendothelioma. Positive immunoreactivity for endothelial markers such as CD34 is useful to rule out other sarcomas.