Fibrosarcoma

When these tumours involve soft tissues they occur most often in external sites, such as the extremities, rather than internally. No specific radiographic features are present, but arteriography demonstrates the vascularity of the tumours, which is a prognostic indicator (the greater the vascularity, the poorer the outlook). Patients frequently have pathologic fractures at the time of diagnosis. Because the tumour infiltrates adjacent soft tissues, or sometimes bone, recurrence after surgery is common. An infantile form occurs that has a much better prognosis than fibrosarcoma in adults. In infants severe bone deformity and marked osseous erosions are frequently seen.

Fibrosarcomas of bone are large, destructive, infiltrating tumours consisting of fibrous tissue which ranges from being poorly differentiated to well differentiated, and which does not produce cartilage, osteoid, or bone. Their prognosis is poorer than for fibrosarcomas of soft tissue. The tumour may arise de novo within the bone or develop in bones involved in Pagets disease, osteonecrosis or chronic osteomyelitis; it also may develop through dedifferentiation of chondrosarcoma or other neoplasm. The sites affected most commonly are the long tubular bones (especially the metaphysis or metadiaphysis), bones about the knee, and bones of the pelvis. From the metaphysis the tumour may spread into the epiphysis.

Radiographically, fibrosarcomas of bone appear as aggressive processes with osteolytic foci with bone destruction of the motheaten, geographic or permeative pattern and little osteosclerosis or periostitis. The absence of ossification or calcification of the tumour is important diagnostically.

DR