Angiosarcoma of the Breast

Definition

All grades are characterized by infiltration of breast parenchyma by cells exhibiting vascular differentiation
Low grade tumors
- Prominent freely anastomosing vascular channels
- Papillary growth and endothelial tufting minimal to absent
- Cytologic atypia may be difficult to identify even after extensive sampling
Intermediate grade tumors
- Freely anastomosing vascular channels
- Papillary growth and endothelial tufting
- May have focal solid areas with polygonal or spindle cells
High grade tumors
- Prominent solid areas of clearly malignant cells
  - Polygonal and spindled cells
- Blood lakes and necrosis are common
- Vascular channels may be difficult to identify
  - May require extensive sampling, especially at edge of lesion
- Demonstration of vascular nature may require immunohistology