Osteosarcoma is the most common primary bone sarcoma. The peak incidence is in adolescence, but it can also occur as a secondary malignancy in older adults. The rapidly growing long bones of the knee and shoulder are the most commonly affected. Treatment always includes chemotherapy and wide surgical resection.



  • Most patients are between 13 and 17 years of age

  • Second smaller peak of incidence after 65 years of age, often as secondary cancer

  • Rare younger than 6 years of age

  • Persistent bone pain; symptoms for 3 to 6 months


  • Metaphyseal, eccentric (90%)

  • Diaphyseal less common (5% to 10%)

  • Distribution: approximately 70% in long bones, more than 50% about the knee; frequency is (1) distal femur, (2) proximal tibia, and (3) proximal humerus


  • Lytic portions typically have nongeographic margins

  • Cortical destruction

  • Soft tissue mass seen in the majority of cases (80%)


  • Osteoid matrix

  • Minority of tumors demonstrate little or no visible mineralization on radiographs


  • Osteoid matrix, appearing as “fluffy” or “cloudlike” opacification ( left and right ).

  • Note mineralizing soft tissue mass on left ( arrow ). Note the aggressive, “hair-on-end” ( arrow ) periosteal reaction ( right ).

  • Many lesions demonstrate mixed lysis and sclerosis, representing osteoid matrix ( left and right ).

  • A pathologic fracture through an osteosarcoma ( left ); 5% to 10% of lesions have a diaphyseal location.

  • Absence of matrix is seen in a minority of lesions, as in this proximal humerus lesion ( right ). A wide zone of transition is seen in all lesions.

  • Bone scan of a proximal tibia tumor shows intense uptake ( left ). Note the less intense uptake in the ipsilateral distal femur and ankle due to disuse osteopenia and hyperemia.

  • Fused PET/CT scans of a proximal humerus tumor showing hypermetabolic activity in both bone and soft tissue components ( right ).

  • CT scans demonstrate dense osteoid matrix in proximal tibia ( left ) and proximal humerus lesions ( right ).

  • The humerus lesion also shows less mineralized posterior soft tissue component ( arrow ).

  • T1 ( left ) and T2 ( right ) MRIs are useful in demonstrating the extent of marrow replacement and extraosseous tumor involvement ( right ).

  • Note the typical absence of prominent surrounding soft tissue and marrow edema ( right ).

  • Most metaphyseal lesions (75% to 90%) extend across the epiphyseal plate, as seen on T1 ( left ) and T2 ( right ) MRIs.

  • The most common appearance on T2-weighted sequences is high intensity ( right ).

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