• 1% of all bone neoplasms
  • 5-25 years
  • M:F = 2.7:1
  • Mono-arthropathy
  • Epiphysis of a long bone
  • 50% around knee
  • Proximal femur and humerus commonly involved
  • Eccentric in epiphysis
  • With partial closure of growth plate, extends to metaphysis
  • Apophysis and sesamoid bones may be involved
  • Calcaneus and talus may be involved
  • Commonest tumor of patella
  • Spherical or lobular
  • Fine sclerotic margin
  • 1-4 cm in size
  • Matrix mineralization in 30%
  • Linear metaphyseal periostea reaction seen in long bones
  • Fluid fluid levels in MRI when secondarily involved by aneurysmal bone cysts
  • A low signal intensity rim is characteristic 
  • Differentials: Brodie abscess in children. Adults – subchondral cysts, clear cell chondrosarcoma 
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Weatherall, Paul T., et al. “Chondroblastoma: classic and confusing appearance at MR imaging.” Radiology 190.2 (1994): 467-474.

Rybak, Leon D., Daniel I. Rosenthal, and James C. Wittig. “Chondroblastoma: radiofrequency ablation—alternative to surgical resection in selected cases.” Radiology 251.2 (2009): 599-604.