Ultrasound features of osteosarcoma of the mandible--a first report.

Ultrasound imaging is becoming widely used in the head and neck region as a first-line investigation to assess soft tissue swellings. Clinicians should be aware of the potential of diagnostic ultrasound to identify important signs of malignant disease involving bone. Involvement of the mandible by osteosarcoma is uncommon. A young adult patient presented with facial swelling and an apparently infected lower third molar extraction socket. Subtle signs were missed on dental radiographs. Diagnostic ultrasound investigation was pivotal in identifying sinister signs: namely, soft tissue mass associated with bone thinning, erosion, expansion, and the "sunray" appearance of the buccal cortex, which were suggestive of osteosarcoma. These findings enabled priority to be given to subsequent investigations using other modalities. We present a first report of the ultrasound features of osteosarcoma of the mandible and consider this to be a useful modality in an initial investigation.