Conventional Osteosarcoma

  • Etiology: malignant bone forming tumor
  • Imaging:
    — Location: most often near metaphyses of long bones (distal femur (75%), proximal tibia, proximal humerus) and extends into epiphysis in 80%
    — Lytic or blastic: lytic
    — Matrix: osteoid, chondroid, fibrous
    — Zone of transition: (wide, narrow)
    — Periosteal new bone or cortical destruction: extensive periosteal reaction (sunburst, Codman’s triangle) and permeative / moth eaten cortical destruction
    — Additionally: extensive extraosseous soft tissue mass
    — Radiograph: lytic and sclerotic, sunburst / spiculated periosteal reaction, cortical destruction, soft tissue mass with osteoid, Codman triangle
    — MRI: non-mineralized osteoid is T1WI iso/hypointense and T2WI hyperintense, osteoid is dark on all sequences, viable tumor enhances, make sure to assess the neurovascular bundle, look for skip metastases in bones
  • Complications: 10-20% metastatic to lung, bone, skip metastasis to bone
  • Clinical: most common malignant primary tumor of children + young adults, peak age is 13-16 years old, 80% of osteosarcoma

Radiology Cases of Conventional Osteosarcoma

Radiograph of osteosarcoma of the femur
AP and lateral radiographs of the right femur shows permeative cortical destruction throughout the diaphysis of the femur with associated diffuse sunburst periosteal reaction and a Codman’s triangle.
Radiograph and CT of osteosarcoma of spine
AP and lateral radiographs of the lumbar spine taken during a CT myelogram show loss of height of the L3 vertebral body and sclerosis of its posterior elements. Axial CT myelogram through the L3 vertebral body shows lytic lesions in the vertebral body and an expansile sclerotic appearance of the posterior elements with periosteal reaction.

Gross Pathology Cases of Conventional Osteosarcoma

Gross pathological image of osteosarcoma
Gross pathological image of the tibia shows an aggressive bone lesion with cortical bone destruction and extensive periosteal reaction.