Primary bone tumors are rare, accounting for less than 1% of all malignant tumors.

Plain radiographs
- Plain radiographs can often predict the probable histology of a potentially malignant bone lesion.
MRI
- MRI is the imaging procedure of choice to evaluate primary bone tumors.
- MRI is invaluable in surgical planning as it demonstrates the intraosseus and soft tissue involvement of the tumor and tumor extension.
- MRI is also helpful in evaluating possible malignant degeneration of osteochondromas by allowing accurate measurements of the cartilage cap.
CT
- CT scans are generally less useful than MRI for assessing primary bone tumors.
- CT is helpful in defining the integrity of the cortex and distribution of calcification.

Destruction of bone with sunburst appearance.

Black Arrowheads : Destroyed cortex.

Mass with calcification
On plain radiographs, chondrosarcoma is a fusiform, lucent defect with scalloping of the inner cortex and periosteal reaction.
Extension into the soft tissue may be present as well as punctate or stippled calcification of the cartilage matrix.

Calcified cartilaginous mass arising from a flat bone in a patient with unfused epiphyses.

MR: White arrows : Mass with calcification. Arrowhead is pointing to femur.