osteosarcoma

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osteosarcoma

[¦äs·tē·ō·sär′kō·mə]
(medicine)
A malignant tumor principally composed of anaplastic cells of mesenchymal derivation. Also known as osteogenic sarcoma.
References in periodicals archive ?
Medullary extension of parosteal osteosarcoma has been seen in 22% to 58% of patients, and this finding itself is not considered significant in the prognosis.
Grossly, parosteal osteosarcomas are hard ossified masses arising from the cortical surface.
The presence of any high-grade component warrants the diagnosis of dedifferentiated parosteal osteosarcoma (Figure 2, B).
The most well-recognized histologic pattern of parosteal osteosarcoma is the presence of paralleled trabecular bone with intervening spindle cell stroma, the so-called streamer pattern (Figure 2, C).
Cartilage differentiation is encountered in parosteal osteosarcoma in up to 55% of cases.
Early studies (13,14) demonstrated characteristic cytogenetic change with supernumerary ring chromosomes or giant marker chromosomes carrying amplified DNA materials from the 12q13-15 region in parosteal osteosarcoma.
Parosteal osteosarcoma is one of the most frequently misdiagnosed entities in bone and soft-tissue tumors.
For periosteal osteosarcoma, the radiological features differ from those of parosteal osteosarcoma by the finding of a fusiform growth pattern and the presence of Codman triangles.
Grade 1 (Low Grade) Low-grade central osteosarcoma Parosteal osteosarcoma Adamantinoma Grade 2 Periosteal osteosarcoma Grade 3 (High Grade) Ewing sarcoma/PNET Conventional osteosarcoma Telangiectatic osteosarcoma Mesenchymal chondrosarcoma Small cell osteosarcoma Secondary osteosarcoma High-grade surface osteosarcoma Dedifferentiated chondrosarcoma Dedifferentiated chordoma Malignant giant cell tumor