Osteosarcoma ung thư xương

Osteosarcoma Kiều Thị Huyền-NT45  Osteosarcomas are malignant  bone-forming tumors. They are the second most common primary bone tumor after  multiple myeloma, accounting for ~20% of all primary bone tumors Epidemiology Primary osteosarcoma typically occurs in young patients (10-20 years) with 75% taking place before the age of 20  Secondary osteosarcoma occurs in the elderly, usually secondary to malignant degeneration of Paget disease, postradiotherapy for other conditions,  osteoblastoma  Location Primary osteosarcomas typically occur at the metadiaphysis of long bones in the appendicular skeleton, most commonly at the following sites:  femur: ~40% (especially distal femur)  tibia: ~16% (especially proximal tibia)  Classification  primary osteosarcoma ◦ intramedullary/central     conventional osteosarcoma: most common (75-80%) low-grade central osteosarcoma telangiectatic osteosarcoma small cell osteosarcoma ◦ surface  parosteal osteosarcoma  high-grade surface osteosarcoma  secondary osteosarcoma Plain radiograph Conventional radiography continues to play an important role in diagnosis Typical appearances of conventional high-grade osteosarcoma include:  medullary and cortical bone destruction  wide zone of transition  aggressive periosteal reaction  ◦ Codman triangle ◦ lamellated (onion skin) reaction: less frequently seen  soft-tissue mass Telangiectatic  osteosarcomas Parosteal osteosarcoma CT  The role of CT is predominantly utilized in assisting biopsy and staging MRI  MRI is proving an essential tool to determine accurate local staging and assessment for limb-sparing resection, particularly for evaluation of intraosseous tumor extension and soft-tissue involvement Evaluation of the growth plate is also essential as up to 75-88% of metaphyseal tumors cross the growth plate into the epiphysis MRI Differential diagnosis General differential considerations include the following:  osteomyelitis  other tumors  ◦ metastatic lesion to bone ◦ Ewing sarcoma ◦ aneurysmal bone cyst Treatment and prognosis  A course of multidrug chemotherapy precedes surgery to downstage the tumor, followed by wide resection of the bone and insertion of an endoprosthesis The outcome depends on different factors such as age, sex, site, size, and type but the most important predictor is the histologic degree of necrosis post-induction chemotherapy ... Classification  primary osteosarcoma ◦ intramedullary/central     conventional osteosarcoma: most common (75-80%) low-grade central osteosarcoma telangiectatic osteosarcoma small cell osteosarcoma ◦... telangiectatic osteosarcoma small cell osteosarcoma ◦ surface  parosteal osteosarcoma  high-grade surface osteosarcoma  secondary osteosarcoma Plain radiograph Conventional radiography continues to.. .Osteosarcoma Kiều Thị Huyền-NT45  Osteosarcomas are malignant  bone-forming tumors. They are the second most common