OBJECTIVETo study the clinical manifestations, radiologic findings, pathologic diagnosis and differential diagnosis of primary osteosarcoma in elderly patients.

METHODSTwelve cases of primary osteosarcoma occurring in patients older than 60 years were encountered during the period from 1985 to 2010. The clinical manifestations, radiologic features and pathologic findings were studied and the follow-up data were analyzed.

RESULTSThe sites of involvement included long bones (number = 7), ilium (number = 1), craniofacial bones (number = 2) and soft tissue (number = 2). Radiologic examination showed a mixture of osteosclerotic and osteolytic lesions in 10 patients, soft tissue lesions with high-density areas in 2 patients and soft tissue lesions with periosteal reaction in 8 patients. Histologically, most cases showed features of conventional osteosarcoma. There were 2 cases of malignant fibrous histiocytoma-like osteosarcoma, 2 cases of chondroblastic osteosarcoma and 1 case of well-differentiated intraosseous osteosarcoma. Immunohistochemical study played little role in pathologic diagnosis. Ten patients had undergone amputation, including one patient who had received adjuvant chemotherapy beforehand. Nine patients had follow-up information available. Three of them died of lung metastasis and 1 died of cardiovascular disease.

CONCLUSIONSPrimary osteosarcoma rarely occurs in elderly patients and can easily be missed. Correlation with clinical, radiologic and histologic features is important for arriving at a correct diagnosis.