Fact-sheet: Chondrosarcoma
Updated on 09/17/2021 at 12:16 PM
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Definition
Malignant cartilaginous tumor. It is the most common primary malignant bone tumor in adults.
Clinical features
Tumor occurring in adults, with a male predominance, between 30-50 years of age.
90% primary, rarely secondary to malignant degeneration of an enchondroma or osteochondroma, Paget disease, or radiation-induced.
Polymorphic bone locations, endosteal (central) or periosteal.
Predominates in the pelvis, proximal femur, and knee.
Clinical presentation depends on the site involved, with possible delayed diagnosis due to slow growth
Radiography
Central chondrosarcoma (90%):
- lesion arising from the medullary cavity, metaphyseal or metadiaphyseal, often large
- appearance similar to enchondroma if low-grade
- cartilaginous matrix
- aggressive or moth-eaten appearance if high-grade -/+ soft tissue invasion
Periosteal chondrosarcoma:
- calcified soft tissue mass
- destroys the outer aspect of the cortex
Clear cell chondrosarcoma (very rare):
- variant affecting the epiphyses of long bones
- lytic lesion with well-defined margins surrounded by osteosclerosis
- cortical breakthrough & calcifications rare
- resembles a chondroblastoma (in which case MRI will be helpful)
CT
Central chondrosarcoma
- better assessment of dimensions, relationships, cortical lysis, and calcifications
- cartilaginous density (approx. 50 HU)
- essential for staging
MRI
Central chondrosarcoma:
- T2 hyperintensity
- septa and contours in hyposignal
- calcifications hypointense on T1 and T2
- arc-and-ring enhancement after IV gadolinium
Clear cell chondrosarcoma (very rare):
- intermediate T1 cartilaginous signal - T2 hyperintensity, different from chondroblastoma (hypoT1, hypoT2)
Nuclear medicine
Constant, nonspecific uptake.
Useful for follow-up of an exostosis or enchondroma in the setting of Ombredanne or Ollier disease if a previously silent lesion becomes hypermetabolic.
Useful for staging
Management
Histologic confirmation: biopsy (surgical biopsy recommended).
Surgical treatment
Differential diagnosis
EXOSTOSIS. Radiologic signs suggestive of malignant transformation of an exostosis:
- increase in size in adulthood
- lucencies or lysis at the base
- cartilaginous cap > 2 cm
- appearance of irregularities in the calcifications of the cartilaginous cap or of distant calcifications
- change in signal
- soft tissue invasion
- hypermetabolic uptake on scintigraphy
ENCHONDROMA
PERIOSTEAL OSTEOSARCOMA
CHONDROBLASTOMA and GCT (Versus epiphyseal clear cell chondrosarcoma)