Chondroblastic osteosarcoma secondary to fibrosarcoma: A case report and literature review.

Osteosarcoma, which is most common in non-blood systemic tumors, accounts for 20% of primary bone malignancies. Primary osteosarcoma usually occurs in young individuals aged 10-20 years, while secondary osteosarcoma is more common in the elderly. It had been reported that secondary osteosarcoma may be associated with osteofibrous dysplasia, bone infarction, chondrosarcoma or osteogenesis imperfecta. However, osteosarcoma secondary to fibrosarcoma has rarely been reported. The current study presents the rare case of a female with chondroblastic osteosarcoma secondary to fibrosarcoma. The patient was relatively young and suffered from more than one type of cancer. The course of the disease lasted for >20 years. This case study provides general knowledge of osteosarcoma, and discusses its clinical presentation, diagnosis, treatment and prognosis.