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File:IPLab7Osteosarcoma15.jpg|This is a high-power photomicrograph of the tumor demonstrating the anaplastic cell morphology and multiple mitotic figures (arrows).
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== Study Question ==
* <spoiler text="What is the incidence and age distribution of osteosarcomas?">Osteosarcoma is the most common primary malignant tumor of bone exclusive of myeloma and lymphoma and accounts for approximately 20% of primary bone cancers. Males are more commonly affected than females (1.6:1). Osteosarcoma occurs in all age groups but has a bimodal age distribution. Approximately 75% occur in patients younger than 20 years of age. The smaller second peak (secondary osteosarcoma) occurs in elderly patients who suffer from conditions known to be associated with the development of osteosarcoma (Paget’s disease, bone infarcts, and prior irradiation).</spoiler>
* <spoiler text="What are the most common locations for osteosarcomas?">Osteosarcomas usually arise in the metaphyseal region of the long bones of the extremities, and almost 60% occur about the knee. The location, in descending order of frequency, is distal femur, proximal tibia, proximal humerus, and proximal femur.</spoiler>
* <spoiler text="What are some of the risk factors associated with the pathogenesis of osteosarcoma?">Gene mutations are fundamental to the development of osteosarcoma. Patients with hereditary retinoblastomas have a several hundred-fold greater risk of developing osteosarcoma. Mutations in the p53 suppressor gene (Li-Fraumeni syndrome) has been implicated in the development of most nonhereditary osteosarcomas as well as many other types of cancer. Interestingly, many osteosarcomas develop at sites of greatest bone growth where bone cell mitotic activity is at its peak--e.g., the base of the femoral growth plate where primary spongiosa is being formed and in Pagetic bone with its frenzy of bone formation and resorption.</spoiler>
* <spoiler text="What is the prognosis for patients with osteosarcoma?">Osteosarcomas are aggressive neoplasms that spread through the bloodstream, and at the time of diagnosis, approximately 20% of patients have demonstrable pulmonary metastases. In those who die of the neoplasm, 90% have metastases to the lungs, bones, brain, and elsewhere. With current treatment regimens the long-term survival rate has been increased to approximately 60% from the historic controls of 25%.</spoiler>
{{IPLab 7}}
[[Category: IPLab:Lab 7]]