The threat of misdiagnosis of primary osteosarcoma over the age of 60: a series of seven cases and review of the literature
PURPOSE To examine the imaging characteristics of osteoblastic osteosarcoma in older patients, we compared them with those in adolescents because the radiological features of osteosarcoma can be atypical in elderly patients. MATERIAL AND METHODS 29 cases of adolescent patients and 12 patients older than 40 years of age were reviewed. All cases were pathologically confirmed as osteoblastic osteosarcoma. The comparative factors were tumor location, plain radiological features including periosteal reactions, and the degree of soft tissue mass with magnetic resonance (MR) imaging. RESULTS Older patients demonstrated frequent osteolytic findings (83.3%), and none of the tumors showed a significant major periosteal reaction. Seven (58.3%) of the 12 tumors had no soft tissue mass (grade 0) and only three (25%) had a grade 3 mass. The differences in the two groups were statistically significant (P<0.001). CONCLUSION In older patients, primary osteosarcoma should be considered when making a differential diagnosis of osteolytic lesions without any periosteal reactions and small soft-tissue extensions. In cases with atypical findings, the morphology of specimens (aspiration, core, or surgical biopsy) from the lesion should be recommended when making an accurate diagnosis.