The Many Faces of Osteosarcoma

Abstract Introduction Primary Intramedullary Osteosarcoma

Surface Osteosarcoma Extraskeletal Osteosarcoma Secondary Osteosarcoma

Conclusions Source Information References

Secondary Osteosarcoma

Most osteosarcomas occur as primary neoplasms. However, both osseous and soft-tissue osteosarcomas can be secondary lesions (5%-7% of all osteosarcomas) resulting from malignant transformation within a benign process (1). The vast majority of these secondary osteosarcomas are associated with Paget disease (67%-90% of cases) (Figure 18) or previous osseous or extraskeletal irradiation (6%-22%) (1,2,3). The frequency of malignant transformation to osteosarcoma in Paget disease varies widely, from 0.2% in patients with limited involvement to as much as 7.5% in those with extensive skeletal manifestations (96,97). Similarly, the estimates of radiation-induced osteosarcoma show a wide range of prevalence, from 0.02% to 4%, that is related to exposure dose (usually >1,000 cGy) (98,99). Preexisting conditions that less commonly lead to osteosarcoma include osteonecrosis, fibrous dysplasia, metallic implants, osteogenesis imperfecta, chronic osteomyelitis, and retinoblastoma (particularly the familial bilateral type associated with a deficient oncogene suppressor on chromosome 13) (1).

Patients with secondary osteosarcoma are usually middle-aged or in late adulthood, accounting for a small second peak of prevalence in this older age group. Radiologic evidence of the long-standing underlying condition is usually obvious, as is the more aggressive bone destruction in the area of malignant transformation. Large, associated soft-tissue masses are also typical of secondary osteosarcoma (Figure 18).

Pathologically, the lesions are usually composed of high-grade anaplastic tissue and produce little or no mineralized matrix, and this aggressiveness results in a dismal prognosis. Despite all the treatment regimens that have been employed, the 5-10-year survival rate is often extremely poor and less than 5% (1,2,3).

Abstract Introduction Primary Intramedullary Osteosarcoma

Surface Osteosarcoma Extraskeletal Osteosarcoma Secondary Osteosarcoma

Conclusions Source Information References