Table 3 Differential diagnostic features
From: Chondromyxoid fibroma-like osteosarcoma: a case series and literature review
Characteristic | CMF-OS | CMF | LGCO | CHS | COS |
|---|---|---|---|---|---|
Age (years) | All ages | All ages, preferably < 30 | 30–40 | > 40 | 10–14 and > 40 |
Site | Craniofacial part; femur | Proximal tibia, distal femur; ilium | Distal femur, proximal tibia | Bones of the pelvis; proximal femur, proximal humerus, distal femur; rib | Distal femur, proximal tibia, proximal humerus |
Location in the long bone | Variable | Metaphysis; eccentric in long bones | Metaphysis, diametaphysis | Metaphysis or Diaphysis; Centric in long bones | Metaphysis |
CR | poorly defined osteolytic, osteogenic or expansive lesion | Well-defined osteolytic lesion | Large, lytic coarsely trabeculated lesion with a focal aggressive feature | Osteolytic lesion with endosteal scalloping; cortical thickening | Large, poorly defined, mixed lytic and blastic mass |
CT | Cortex destruction | Sclerotic margin | Cortex destruction; periosteal reaction | Mineralization; cortex erosion or destruction | Mineralization, ossification; cortex destruction; periosteal reaction |
MRI | Soft tissue mass; Soft tissue and bone marrow oedema | Peripheral nodular enhancement; no bone marrow or soft tissue oedema | Soft tissue extension; difficult to distinguish from COS | Ring-and-arc enhancement; soft tissue oedema | Soft tissue mass; soft tissue and bone marrow oedema |
Histology | Loose aggregates of cells supported in a highly myxoid stroma; Neoplastic bone | Lobular pattern with stellate or spindle-shaped cells in a myxoid background | Hypocellular to moderately cellular fibroblastic proliferation with variable amounts of osteoid production; neoplastic bone | Abundant blue-grey cartilage matrix production; atypical chondrocyte varying in size and shape with enlarged, hyperchromatic nuclei | Neoplastic cells with severe anaplasia and pleomorphism; neoplastic bone |
Immunohistochemistry | Vimentin (+); S100 (−) | S100 (+); collagen II, SOX9 (+) in the centre of lobules | MDM2, CDK4 (+) | 20% IDH1(+) with IDH R132H antibody | osteocalcin, osteonectin, S100, action, SMA, NSE, CD99 (+); Factor VIII, CD31, CD45 (−) |
Genetic | None | Chromosome 6 aberration | Gain or amplification of MDM2 (12q13–15) | IDH1 mutation | Multiple numerical and structural chromosomal aberrations |