Flashcards in Bones & Joints Deck (253)
Intramedullary chondrosarcoma: Significance of endochondral ossification.
Endochondral ossification does not make it an osteosarcoma.
Intramedullary chondrosarcoma vs. benign cartilaginous tumor: Anatomical clue.
Hands and feet: Generally benign.
Axial skeleton: Usually aggressive.
Intramedullary chondrosarcoma vs. benign cartilaginous tumor: Clinical clue.
If pain, then more likely to be malignant.
Secondary chondrosarcoma: Backgrounds (4).
Dedifferentiated chondrosarcoma: Age group.
Most patients are older than 50 years.
Dedifferentiated chondrosarcoma: Presentation.
Recent increase in pain due to rapid growth of tumor.
Pathologic fracture in most patients.
Dedifferentiated chondrosarcoma: Radiography.
Poorly defined lytic area.
Superimposed radiodensity containing calcifications.
Dedifferentiated chondrosarcoma: Gross pathology.
Component of chondroid tissue.
Component of soft, fleshy, tan-yellow tissue.
Dedifferentiated chondrosarcoma: Histology.
Abrupt transition between
- Chondroid component: Grade 1 chondroid neoplasm (usually) or grade 2.
- Dedifferentiated component: Sarcomatoid, sometimes with heterologous differentiation.
Dedifferentiated chondrosarcoma: Immunohistochemistry (2).
Chondroid component express S100.
Dedifferentiated component expresses sarcoma-related markers (e.g. SMA, CD68).
Dedifferentiated chondrosarcoma: Ploidy.
Chondroid component: Diploid.
Dedifferentiated component: Aneuploid.
Dedifferentiated chondrosarcoma vs. mesenchymal chondrosarcoma (2).
- More gradual transition between components.
- Hemangiopericytoma-like vascular pattern.
Dedifferentiated chondrosarcoma: Prognosis.
Dedifferentiated chondrosarcoma containing MFH component has a worse prognosis than primary MFH.
Mesenchymal chondrosarcoma: Age group.
About 80% of cases occur between 10 and 40 years of age.
Mesenchymal chondrosarcoma: Sites (5).
Mesenchymal chondrosarcoma: Radiography.
Radiolucency with variable mineralization.
Mesenchymal chondrosarcoma: Histology.
Gradual transition between
- Chondroid component: Bland hyaline cartilage.
- Mesenchymal component: Small round blue cells primitive spindle cells surrounding vessels like those of HPC.
Mesenchymal chondrosarcoma: Immunohistochemistry (5).
Chondroid component expresses S100.
- Expresses Sox9.
- May express CD99 in small cells.
- May express NSE in primitive cells.
- Expresses desmin and MSA is there is rhabdomyoblastic differentiation.
Mesenchymal chondrosarcoma: Translocations (2).
t(11;22)(q24;q12) as in Ewing's sarcoma.
t(13;21)(q10;q10) in some tumors.
Clear-cell chondrosarcoma: Sites (3).
- Proximal femur.
- Proximal humerus.
- Distal femur.
Clear-cell chondrosarcoma: Radiography (2).
Discrete lytic lesion with a sclerotic rim.
Cortex is usually intact.
Clear-cell chondrosarcoma: Cytology (3).
- Vesicular chromatin.
- Large nucleolus.
- Abundant, clear.
- Discrete borders.
Few mitotic figures.
Clear-cell chondrosarcoma: Histology
Scattered bony trabeculae or woven bone in the matrix.
Half of cases contain conventional chondrosarcoma.
Clear-cell chondrosarcoma: Special stain.
PAS highlights glycogen in the clear cells.
Clear-cell chondrosarcoma vs. chondroblastoma (2).
- Few or no clear cells.
- No bony trabeculae.
Hemangioma of bone: Sites (2).
Hemangioma of bone: Presentations (2).
May compress facial nerve, spinal cord, or spinal nerve roots.
Hemangioma of bone: Radiography of cranial tumors (2).
Lytic mass with sunburst pattern.
Bulging of inner and outer tables.
Hemangioma of bone: Radiography of vertebral tumors (2).
Lytic mass with vertical striations.
CT: "Polka-dot" pattern.