[Radiologic features of osteosarcoma of the jaw].

Osteosarcoma of the jaw differs from that in other sites because it is less aggressive, rarely metastasizes and appears later in life. The literature lacking a systematic treatise on the radiologic features of this disease, the authors decided to collect the case histories of 9 patients, 5 men and 4 women, 24 to 48 years old, suffering from osteosarcoma of the jaw. Both conventional radiography and CT were used to examine all patients. The accurate study of radiologic findings made it possible to establish 3 basic lesion patterns. The first and very rare one, is characterized by the total absence of neoplastic tissue ossification processes; in this case, the radiologic diagnosis is extremely difficult, even with CT support. The second and more common pattern exhibits evident tumor neo-ossification, the most representative cases present several bone lamellae radiating from the lesion, with a sunburst-like appearance. The disease can be diagnosed with conventional radiography alone, especially in the most advanced cases; CT permits the identification of early forms, missed with conventional methods. The third pattern is characterized by amorphous lesion ossification: there are small areas of structureless ossification and a patchy appearance, separated by non-ossified neoplastic tissue. CT shows tumor ossification missed at conventional radiography. Finally, the authors observed an extremely rare case of parosteal sarcoma of the jaw, considered a variety of osteosarcoma by some pathologists. The lesion presented uniform neo-ossification which was highly sclerotic and separated from cortical bone by a thin layer of radiolucent tissue: both findings were clearly visible with CT. In conclusion, the systemic use of CT has led to a marked improvement in the radiologic diagnosis of osteosarcoma of the jaw.