Musculoskeletal haemangiopericytomas are now considered to be a cellular and more aggressive version of solitary fibrous tumours, and the term has largely been abandoned.
These tumours are most frequently seen in middle-aged adults (~ 4th decade).
Typically they have large vessels especially located at its periphery, and commonly involve the lower limbs (35% of cases), especially the thigh, pelvis and retroperitoneum (25%). Primary osseous lesions are rare.
Radiologically they appear the same as angiosarcomas and haemangioendotheliomas.
Nonspecific soft tissue mass. When involving bone, they are predominantly lytic and may mimic haemangiomas with a course honeycomb appearance.
Dense, well-circumscribed areas of enhancement with early draining veins and shunting. Hemangiopericytomas are described as having a pedicle formed by the arteries supplying the tumour from which vessels branch to encircle the tumour.
Nonspecific soft tissue mass, with a density similar to muscle but demonstrating bright contrast enhancement. CTA may demonstrate large feeding vessels.
Brightly enhancing soft tissue mass, often hyperintense on T2WI, with prominent flow voids, most marked in haemangiopericytomas.
The differential diagnosis for bone tumours is dependent on the age of the patient, with a very different set of differentials for the paediatric patient.
- bone-forming tumours
- cartilage-forming tumours
- chondromyxoid fibroma
- fibrous bone lesions
- bone marrow tumours
- other bone tumours or tumour-like lesions
- aneurysmal bone cyst
- benign fibrous histiocytoma
- giant cell tumour of bone
- Gorham massive osteolysis
- haemophilic pseudotumour
- intradiploic epidermoid cyst
- intraosseous lipoma
- musculoskeletal angiosarcoma
- musculoskeletal haemangiopericytoma
- primary intraosseous haemangioma
- simple bone cyst
- impending fracture risk