Based on their histologic (fine tissue) characteristics, the WHO (World Health Organization) classifies osteosarcomas as follows:
Classification | Subtype |
Primary osteosarcoma | |
Central (medullary) osteosarcoma | |
Classic osteosarcoma
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Teleangiectatic osteosarcoma | |
Intraosseous well-differentiated osteosarcoma (low-grade) | |
Small cell (mesenchymal) osteosarcoma | |
Superficial (peripheral) osteosarcoma | |
Parosseous (juxtacortical) well-differentiated osteosarcomas. | |
Periosteal osteosarcomas, well to moderately differentiated | |
High-grade osteosarcoma (conventional osteosarcoma) (poorly differentiated) | |
Secondary osteosarcoma |
Lodwick classification
By means of the Lodwick classification, it is possible to assess whether the tumor is benign (benign) or malignant (malignant) on an X-ray. Furthermore, it is suitable for the assessment of progression in the case of aggressive behavior of the tumor.
An index for the growth rate of the bone tumor or an inflammatory process is the reaction visible on the X-ray, i.e. the bone structure is modified locally, regionally or diffusely by the tumor. The visible patterns of destruction are classified into the following main groups:
Grade | Growth rate | Bone destruction | Dignity* | Bone tumors |
Grade I | Purely geographic (circumscribed); boundary definable | |||
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Very slow growing | Sclerosis (pathological hardening of here: tissues) and sharp boundary | benign | Chondroblastoma, enchondroma, fibrous bone dysplasia, nonossifying fibroma, osteoid osteoma |
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Slow growing (displacing) | Bone distention > 1 cm and/or no sclerosis | actively benign | Giant cell tumor |
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Mean growth rate(locally invasive) | Total compact penetration (compacta = outer marginal layer of bone). | aggressive benign | Chondro-, osteo-, fibrosarcomas |
Grade II | fast growing | Geographic, with moth-eaten/permeated (without respect for anatomical boundaries) component | predominantly malignant | Chondrosarcoma, fibrosarcoma, malignant fibrous histiocytoma, metastases, osteosarcoma |
Grade III | very fast growing | purely moth-eaten or permeative destruction | malignant | Ewing’s sarcoma |
* biological behavior of tumors; i.e., whether they are benign (benign) or malignant (malignant)The classification is particularly suitable for tumors of a long bone or small bone. However, it is neither sensitive nor specific, so further diagnostic measures are usually indispensable.