Periosteal osteosarcoma of the jaws: Report of 2 cases

Osteosarcoma (OS) occurs most often in the long bones. OS of the jaws has c linical and biologic aspects different from those of the long bones. They t end to occur at an older mean age, pain and swelling are more typical, and prognosis is more favorable. Nearly all OS shows a very prominent central i ntramedullary bone component Only rarely are juxtacortical (peripheral) OS located in the jaws. There are 2 main types of juctacortical OS, periosteal and parosteal. We present 2 cases of OS of the jaws where the clinical, ra diologic, and histologic findings pointed to a diagnosis of periosteal OS. Both patients presented, in fact, with lesions located superficially on the bone surface with no marrow involvement. Both tumors were characterized by the presence of a moderately differentiated chondroblastic tumor with foci of osteoid and bone formation. Periosteal OS should be differentiated micr oscopically from periosteal chondrosarcoma, intramedullary OS with perioste al extension, high-grade surface OS, and parosteal OS. The clinical differe ntial diagnosis was done, in these cases, for epulis, gingival tumors, peri pheral odontogenic fibroma, peripheral ossifying fibroma, pyogenic granulom a, peripheral giant cell granuloma, and mesenchymal malignant tumors.