Chondrosarcoma

 

Epidemiology:

    • >40y
    • clear cell and mesenchymal occur in younger patients (teens-20s)
    • M:F 2:1

 

Common sites:

    • Long bones of the extremities (>50%)
    • Central portions of the skeleton
      • Pelvis
      • Shoulder
      • Ribs
    • Clear cell variant in the epiphysis of long bones
    • Rarely involves the distal extremities
    • intramedullary and juxtacortical subtypes according to site

 

Gross features:

    • large, bulky
    • nodules of gray-white, somewhat translucent glistening tissue
    • spotty calcifications typically
    • predominantly myxoid types have viscous, gelatinous, oozing cut surface
    • central necrosis with cystic degeneration
    • adjacent cortex thickened or eroded

 

Histologic features:

    • production of neoplastic cartilage
      • malignant hyaline and myxoid cartilage
      • infiltrates the marrow and surrounds pre-existing bony trabeculae
    • pushing borders
      • no rim of bone all the way around like enchondroma
    • conventional type (hyaline and/or myxoid):
    • clear cell type:
      • sheets of large malignant chondrocytes
      • abundant clear cytoplasm
      • numerous osteoclast-type giant cells
      • intralesional reactive bone formation
    • dedifferentiated type:
      • high-grade component with morphology of poorly differentiated sarcoma
        • malignant fibrous histiocytoma
        • fibrosarcoma
        • osteosarcoma
    • mesenchymal type:
      • islands of well-differentiated hyaline cartilage surrounded by sheets of small round cells
    • grading:
      • clear cell chondrosarcomas are low-grade
      • mesenchymal chondrosarcomas and dedifferentiated chondrosarcomas are high grade
      • grade 1:
        • mild hypercellularity
        • plump vesicular nuclei with small nucleoli
        • sparce binucleate cells
        • mitotic figures difficult to find
        • mineralized portions of matrix frequently
        • enchondral ossification of cartilage may occur
      • grade 2:
      • grade 3:
        • marked hypercellularity
        • extreme pleomorphism with bizarre tumour giant cells
        • bizarre mitoses
        • more often occurs as part of a chondroblastic osteosarcoma

 

Immunophenotype:

Marker:

Sensitivity:

Specificity:

 

 

 

 

Molecular features:

    •  

 

Other features:

    • painful, progressively enlarging mass
    • radiolograph:
      • prominent endosteal scalloping
      • radiolucency correlates with higher grade
      • thickening of cortex in low-grade tumour
      • eroding through cortex into soft tissue in higher grade
    • may arise from pre-existing enchondroma
    • few develop from osteochondroma, chondroblastoma, or fibrous dysplasia or Paget disease
    • mets to lungs and skeleton

 

References:

    • Robbins 2005
    • WHO book 2002