Angiosarcoma (MSK)

Angiosarcomas, haemangiopericytomas, and haemangioendotheliomas are tumours that arise from vascular structures. They are typically difficult to distinguish from one another on imaging alone.

Angiosarcomas, are the most aggressive of the three, frequently having metastases at the time of diagnosis, and often having local recurrences. They are more frequently seen in males (M:F 2:1) except when seen in the setting of post mastectomy lymphoedema which is clearly more common in women and is known as Stewart-Treves syndrome.

They can occur in:

• skin - 33%
• soft tissues - 24%
• bone - 6%
  • long bones - 60%, esp the tibia (23%), femur (18%) and humerus (13%)
  • pelvis (7%)

Histologically they can contain either haemangiomatous or lymphangiomatous cellular elements, which accounts for them previously being referred to as lymphangiosarcomas or haemangiosarcomas.

Radiologically they appear the same as haemangiopericytomas and haemangioendotheliomas.

X-rays

Nonspecific soft tissue mass. When involving bone, they are predominatly lytic, and may mimic haemangiomas with a course honeycomb appearance.

Angiography

Dense, well-circumscribed areas of enhancement with early draining veins and shunting. Hemangiopericytoma are described as having a pedicle formed by the arteries supplying the tumor from which vessels branch to encircle the tumor.

CT

Non specific soft tissue mass, with density similar to muscle but demonstrating bright contrast enhancement. CTA may demonstrate large feeding vessels.

MRI

Bightly enhancing soft tissue mass, often hyperintense on T2WI, with prominant flow voids, most marked in haemangiopericytomas.