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 or moth eaten cortical destruction
    — Additionally: Extensive extraosseous soft tissue mass
  • Imaging Radiograph:
    — Lytic and sclerotic
    — Sunburst or spiculated periosteal reaction
    — Codman triangle
    — Cortical destruction
    — Soft tissue mass with osteoid
  • Imaging MRI:
    — Non-mineralized osteoid is T1WI iso to 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
  • DDX:
  • Complications: 10-20% metastatic to lung, bone, skip metastases to bone
  • Treatment: Chemotherapy then surgical
  • Clinical:
    — Most common malignant primary tumor of children and 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 of osteosarcoma of the tibia
AP radiograph of the tibia and fibula (left) with a magnified view (right) shows a lesion in the diaphysis of the tibia with permeative cortical destruction and associated 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.

Radiology Cases of Brain Metastasis Due to Conventional Osteosarcoma

CT of brain metastasis from osteosarcoma
Axial CT without contrast of the brain shows a large dense lesion in the posterior aspect of the right cerebral hemisphere which has high density calcification along its most posterior aspect. The lesion is surrounded by low density vasogenic edema.

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.