Osteosarcoma

Key Features

• Accounts for 60% of cases and occurs mostly in adolescents and young adults

• The metaphyses of long tubular bones are primarily affected

• The distal femur accounts for more than 40% of cases, with the proximal tibia, proximal humerus, and mid and proximal femur following in frequency

Clinical Findings

• Pain over the involved area is the usual presenting symptom with or without an associated soft tissue mass

• Patients generally have symptoms for several months prior to diagnosis

• Cardinal signs of bone tumor

  • Pain at the site of involvement, often following slight trauma

  • Mass formation

  • Fracture through an area of cortical bone destruction

Diagnosis

• Laboratory findings may reveal elevated serum alkaline phosphatase or lactate dehydrogenase levels

• Radiographic findings show

  • Permeative destruction of the normal bony trabecular pattern with indistinct margins

  • Periosteal new bone formation and lifting of the bony cortex may create a Codman triangle

  • Soft tissue mass plus calcifications in a radial or sunburst pattern

• MRI is more sensitive than CT scanning in defining the extent of the primary tumor

• CT scan of the chest and bone scan are essential for detecting metastatic disease

• Positron emission tomography (PET)-CT may be a consideration in monitoring response to therapy

• Bone marrow aspirates and biopsies are not indicated

• Tissue sample is needed to confirm the diagnosis

Treatment

• Chemotherapy is often administered prior to definitive surgery (neoadjuvant chemotherapy)

  • May be administered intra-arterially or intravenously, although the benefits of intra-arterial chemotherapy are disputed

  • Effective agents include doxorubicin, cisplatin, high-dose methotrexate, ifosfamide, and etoposide

• Definitive cure requires en bloc surgical resection of the tumor with a margin of uninvolved tissue

• Amputation, limb salvage, and rotationplasty (Van Ness rotation) are equally effective in achieving local control of osteosarcoma

• Contraindications to limb-sparing surgery include

  • Major involvement of the neurovascular bundle by tumor

  • Immature skeletal age, particularly for lower extremity tumors

  • Infection in the region of the tumor

  • Inappropriate biopsy site

  • Extensive muscle involvement that would result in a poor functional outcome