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| ===Extra skeletal osteosarcoma===
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| On X-ray, extra skeletal osteosarcoma appears as soft tissue density with variable amount of [[calcification]] which represents [[osteoid]] matrix formation, and is seen in approximately 50% of cases.
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| ===Parosteal osteosarcoma===
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| *Large lobulated exophytic, 'cauliflower-like' mass with central dense ossification adjacent to the bone.
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| *'''String sign''': Thin radiolucent line separating the tumor from cortex, observed in 30% of cases.
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| *Tumor stalk: Grows within tumor in late stages and obliterates the radiolucent cleavage plane.
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| *+/- soft tissue mass.
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| *Cortical thickening without aggressive periosteal reaction is often seen.
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| *Tumor extension into medullary cavity is frequently observed.
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| ===Intracortical osteosarcoma===
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| *It typically presents as an oval intracortical geographic osteolytic lesion in the [[diaphysis]] with surrounding [[sclerosis]] and usually measures about 4 cm in length. *Multiple calcific foci can be seen within the lytic region, suggesting osteoid matrix.
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| ===Periosteal osteosarcoma===
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| *Typically seen as a broad-based surface soft-tissue mass causing extrinsic erosion of thickened underlying diaphyseal cortex and perpendicular periosteal reaction extending into the soft-tissue component.
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| ===Low grade osteosarcoma===
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| *Because the [[fibrous dysplasia]] and central low-grade osteosarcoma are so similar histologically, the radiographic features are an extremely important part of the diagnosis.
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| *Radiographic features of low grade osteosarcomas are variable.
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| *Most common pattern is as a large intracompartmental expansile lytic fibro-osseous lesion with coarsely thick or thin incomplete trabeculations. Another less common pattern is as a dense sclerotic lesion.
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| *Cortical erosion and soft tissue extension is also a common feature.
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| ===Telangiectatic osteosarcoma===
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| *Typically seen as an expansile lytic metaphyseal bony lesion.
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| *Geographic bony destruction with wide zone of transition tends to be more common than permeative bony destruction.
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| *Less osteoid matrix compared from conventional type.
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| ==References== | | ==References== |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
On x-ray, osteosarcoma is characterized by medullary and cortical bone destruction, periosteal reaction, tumor matrix calcification and soft tissue mass.[1]
X Ray
Conventional radiography continues to play an important role in diagnosis of osteosarcoma. Typical appearances of conventional high grade osteosarcoma include:[1]
- Medullary and cortical bone destruction.
- Wide zone of transition, permeative or moth-eaten appearance.
- Aggressive periosteal reaction characterized by:
- Sunburst appearance
- Codman triangle
- Lamellated (onion skin) reaction: less frequently seen
- Variable: reflects a combination of the amount of tumor bone production, calcified matrix, and osteoid.
- Ill-defined fluffy or cloud-like cf. to the rings and arcs of chondroid lesions.
Images courtesy of RadsWiki
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Plain film: Osteosarcoma
-
Plain film: Osteosarcoma
|
|
| Subtype
|
X-Ray findings
|
|---|
- Intracortical osteosarcoma
|
- Presents as an oval intracortical geographic osteolytic lesion in the diaphysis with surrounding sclerosis
- Measures approximately 4 cm in length
- Multiple calcific foci can be seen within the lytic region, suggesting osteoid matrix.
|
- Parosteal osteosarcoma
|
- Large lobulated exophytic, 'cauliflower-like' mass with central dense ossification adjacent to the bone.
- String sign: Thin radiolucent line separating the tumor from cortex, observed in 30% of cases.
- Tumor stalk: Grows within tumor in late stages and obliterates the radiolucent cleavage plane.
- +/- soft tissue mass.
- Cortical thickening without aggressive periosteal reaction is often seen.
- Tumor extension into medullary cavity is frequently observed.
|
- Periosteal osteosarcoma
|
- Typically seen as a broad-based surface soft-tissue mass causing extrinsic erosion of thickened underlying diaphyseal cortex and perpendicular periosteal reaction extending into the soft-tissue component.
|
- Telangiectatic osteosarcoma
|
- Typically seen as an expansile lytic metaphyseal bony lesion.
- Geographic bony destruction with wide zone of transition tends to be more common than permeative bony destruction.
- Less osteoid matrix compared from conventional type.
|
- Low grade osteosarcoma
|
- Because the fibrous dysplasia and central low-grade osteosarcoma are so similar histologically, the radiographic features are an extremely important part of the diagnosis.
- Radiographic features of low grade osteosarcomas are variable.
- Most common pattern is as a large intracompartmental expansile lytic fibro-osseous lesion with coarsely thick or thin incomplete trabeculations. Another less common pattern is as a dense sclerotic lesion.
- Cortical erosion and soft tissue extension is also a common feature.
|
- Extra skeletal osteosarcoma
|
- Soft tissue density with variable amount of calcification which represents osteoid matrix formation, and is seen in approximately 50% of cases.
|
References
Template:WH
Template:WS
Plain film: Osteosarcoma
Plain film: Osteosarcoma
