|MYOSITIS OSSIFICANS||OSTEOGENIC SARCOMA|
Rapidly-growing, painful swelling and joint stiffness;|
History of trauma.
Local pain, swelling and limp;|
Night-time awakenings with bony pain;
|RADIOLOGICAL||Rx/CT: calcified peripherical rim with a radiolucent cleft between the lesion and the cortical bone.||Rx/CT: Periosteal reaction, Codman’s triangle, sunburst sign; lobulated mass (cauliflower-like).|
MRI: early T2-weighted hyperintensity (oedema) and later hypointense rim in all sequences;|
Usually no contrast-enhancement.
|MRI: heterogeneous or solid contrast-enhancement.|
“zonal pattern organization”:|
1. Peripherical mature lamellar bone;
2. Middle zone: immature osteoid matrix;
3. Inner zone: proliferating fibroblast tissue.
Spindle/polygonal, malignant mesenchymal cells; hemorrhagic and necrotic lesions;|
MDM2 and CDK4 +.