Tumor biology and incidence

  • Benign giant cell and chondroid-type lesion
  • Rare, aggressive tumor of bone composed of immature chondroblasts and scant chondroid matrix
  • Predilection for epiphyses of long bones prior to epiphyseal closure
  • Arise in secondary centers of ossification
  • Approximately 5% of benign bone tumors


  • Adolescents most commonly affected
  • 95% of cases ranges from 5 to 25 years old


Male:Female = 3:2


  • Pain in joint adjacent to tumor without history of trauma
  • Swelling
  • Pain often present for months or years; frequently misdiagnosed as chronic synovitis

Physical findings

  • Joint effusion
  • Decreased range of motion
  • Swelling
  • Tenderness to palpation 

Plain films

  • Well-defined round or oval lytic lesions
  • Radiolucent
  • Scalloping or expansion of the cortex not uncommon
  • Punctate or ring calcifications may be present

Most commonly epiphyseal: femur > humerus > tibia > pelvis > tarsal bones


Variable; typically ranges from 1 to 6 cm

Tumor effect on bone
  • Lytic lesion with a well defined (geographic) margin
  • Bulging of overlying cortex can occur due to metaphyseal extension
Bone response to tumor
  • Sclerotic rim of reacitve bone, which can become thicker with time
  • May have a metaphyseal periosteal reaction distal to lesion

Lytic, with possible internal cartilagenous calcifications


May be expanded with metaphyseal lesion

Soft tissue mass


Bone scan

Increased uptake of chondroblastomas on bone scan may be related to tumor hyperemia

CT scan

  • Excellent for visualizing internal calcification
  • Can depict matrix mineralization, soft-tissue extension, and cortical erosion, if present. 
  • Coronal and sagittal reconstructions may be helpful in evaluating extension across physeal plate


  • Typical bright T2-weighted, lobulated chondroid matrix
  • May have variable surrounding medullary edema and periosteal reaction; may be misleading in defining extent of lesion

Differential diagnosis

  • Giant cell tumor (no calcifications, ossification, or sclerotic margin)
  • Clear cell chondrosarcoma
  • Chondromyxoid fibroma
  • Enchondroma
  • Osteomyelitis
  • Hemangioma
  • Fibrous dysplasia and nonossifying fibroma (rare to affect epiphysis)
  • Degenerative joint cyst

Natural history

  • Small and slow-growing; generally do not resolve without surgical management
  • Chondroblatoma of the pelvis is usually more aggressive than lesions in long bones
  • Most patients are close to skeletal maturity; residual deformity after treatment is minimal
  • Patient less than 10 years of age, take care not to damage growth plate
  • Synchronous and metachronous metastases are very rare, but have been reported


  • Gross: grey tan tissue; chondroid component not usually seen
  • Microscopic: proliferating chondroblasts (mononuclear cells); round to oval in shape with well-defined cell margins
    • Variable amounts of chondroid, which stains pink rather than having a typical bluish appearance, are present
    • Chicken wire calcification may occur
    • Numerous giant cells may be present; differentiation from giant cell tumor can be difficult

Diagnosis and treatment

  • Lesion must be well visualized at resection; open joint if required
  • Curettage is treatment of choice; must be thorough
  • Phenol and liquid nitrogen generally not used for fear of growth plate or articular cartilage damage
  • Defect packed with autograft or allograft
  • Recurrence rate from 10% to 30%


  • Complications related to surgical treatment
    • Infection
    • Premature physeal closure
    • Failure of allograft
    • Development of degenerative joint changes
  • Pathologic fracture through lesion (rare) 
  • Premature physeal closure, subsequent limb-length discrepency or angular deformity (rare) 
  • Malignant transformation (very rare)

Recommended reading

Suneja R, Grimer RJ, Belthur M, Jeys L, Carter SR, Tillman RM, Davies AM. Chondroblastoma of bone: long-term results and functional outcome after intralesional curettage.J Bone Joint Surg Br. 2005 Jul;87(7):974-8.

Ramappa AJ, Lee FY, Tang P, Carlson JR, Gebhardt MC, Mankin HJ. Chondroblastoma of bone. J Bone Joint Surg Am. 2000 Aug;82-A(8):1140-5.