Osteosarcoma

: A cancer of the bone that is most common in children. Also called osteogenic sarcoma.

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SYN: osteogenic sarcoma.

- parosteal o. low-grade o. arising on the surface of bone without involvement of the underlying marrow, usually occurring as a heavily ossified mass of the distal femur in women in the third and fourth decades of life.

- periosteal o. chondroblastic o. occurring on the surface of bones without involvement of the marrow; usually presents in adolescents and young adults as a lucent defect with bone spicules extending into soft tissues. Histologically, the tumor is intermediate to high grade, and the cartilage is lobulated.

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os·teo·sar·co·ma -sär-'kō-mə n, pl -mas also -ma·ta -mət-ə a sarcoma derived from bone or containing bone tissue called also osteogenic sarcoma

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n.

a highly malignant tumour arising from within a bone, usually in the metaphysis of the long bones of the body and especially around the knee and the proximal end of the humerus. It is usually seen in children and adolescents but can occur in adults of all ages, occasionally in association with Paget's disease of bone. In children the usual site for the tumour is the leg, particularly the femur. Secondary growths (metastases) are common, most frequently in the lungs (though other sites, such as the liver, may also be involved). The symptoms are usually pain and swelling at the site of the tumour and there is often a history of preceding trauma, although it is doubtful whether this contributes to the cause. Treatment of disease localized to the primary site was traditionally by amputation of the limb; limb-sparing surgery is now possible after neoadjuvant chemotherapy, with replacement of the diseased bone by a metal prosthesis. Many centres also give adjuvant therapy in an attempt to kill any microscopic tumour that might have already spread. The drugs used include doxorubicin, cisplatin, vincristine, cyclophosphamide, and methotrexate.

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os·teo·sar·co·ma (os″te-o-sahr-koґmə) [osteo- + sarcoma] a malignant primary neoplasm of bone composed of a malignant connective tissue stroma with evidence of malignant osteoid, bone, or cartilage formation. Classical osteosarcoma is a poorly differentiated tumor affecting mainly young adults, most often involving the long bones, and is classified as osteoblastic, chondroblastic, or fibroblastic according to which histologic component predominates. Called also osteogenic sarcoma. osteosarcomatous adj