Which radiological feature is characteristic of osteosarcoma?

The characteristic radiological feature of osteosarcoma is the sunburst pattern. This pattern arises from the aggressive nature of osteosarcoma, which is a malignant bone tumor commonly found in the metaphysis of long bones. The sunburst appearance is due to the radiating periosteal reaction from the tumor growth, where the tumor lifts the periosteum and causes new bone formation that projects outward, resembling rays of sunlight.

This feature helps clinicians differentiate osteosarcoma from other lesions. In particular, the presence of this pattern indicates an aggressive behavior of the tumor, which often correlates with a higher grade and potential for metastasis.

The other features listed are characteristic of different conditions; for instance, the apple core lesion is typically associated with colorectal cancer, and onion skinning is seen in conditions like osteomyelitis or Ewing's sarcoma. Ground glass appearance is often linked to fibrous dysplasia or certain types of benign bone tumors. Thus, recognizing the sunburst pattern is crucial for the diagnosis and management of osteosarcoma.