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
- 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:
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Sensitivity:
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Specificity:
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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