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Table 1 Main differences between myositis ossificans and osteogenic sarcoma

From: Myositis ossificans mimicking sarcoma: a not so rare bioptic diagnostic pitfall

CLINICAL Rapidly-growing, painful swelling and joint stiffness;
History of trauma.
Local pain, swelling and limp;
Night-time awakenings with bony pain;
Pathological fractures;
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.
HISTOLOGICAL “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 +.
  1. Abbreviations: CT computed tomography, MRI magnetic resonance imaging