What radiographic features are considered when evaluating a suspected bone tumor?
When evaluating a suspected bone tumor, morphologic features, location in a bone (epiphysis, metaphysis, diaphysis), distribution within the skeleton (axial vs. appendicular), presence of tumor matrix, periosteal reaction, and/or presence of a soft tissue mass are considered. Morphologic features to consider are the pattern of bone destruction and the size, shape, margins, and zone of transition of the lesion. A geographic lesion with a sharp border suggests a nonaggressive or benign lesion, whereas a poorly defined margin, especially one associated with cortical destruction, favors malignancy. Periosteal reaction reflects the rate of growth of the underlying lesion. Slow-growing lesions may produce a laminated periosteal reaction with uniform, wavy layers. Malignant lesions that grow in spurts can produce an “onion-skin” pattern, whereas aggressive lesions with rapid growth are associated with a “sunburst” or “hair-on-end” periosteal reaction. Codman triangle is the uplifting of the periosteum in a triangular configuration and can be seen with benign and malignant lesions.