Learning Radiology xray montage
 
 
 
 
 
 

Chondroblastoma
Codman Tumor

General Considerations

  • Rare, benign bone tumor that arises in the epiphysis of long bones in skeletally immature patients
  • Usually occurs under the age of 20; males greater than females
  • Most common locations are in lower extremity (70%)
    • 50% occur around knee
    • Femur most common
      • Most chondroblastomas of the proximal femur occur in the greater trochanter
    • Proximal tibia
    • Proximal humerus
      • Most occur in humeral head
    • About 10% occur in the small bones of the hands and feet
  • May also occur in apophyses
  • Most common tumor of patella

Clinical Findings

  • Pain
  • Limitation of motion
  • Redness
  • Swelling

Imaging Findings

  • Conventional radiographs are usually diagnostic
  • Geographic lytic lesion arising in the epiphysis of a child
  • May have scalloping or expansion of epiphyseal cortex
  • May extend to adjacent metaphysis
  • Eccentric
  • Up to half may have internal calcifications
  • Well-defined sclerotic margin
  • CT or MRI are used to evaluate
    • Extent of involvement of epiphysis
    • Proximity of lesion to articular cartilage
  • On MRI
    • Low signal intensity on T1
    • High or variable intensity on T2

Differential Diagnosis

  • Counterpart of chondroblastoma in a child is giant cell tumor (GCT) of an adult
    • GCT arise later in life (20-30)
    • Frequently extend to metaphysis

Treatment

  • Curettage
  • Packing with allograft or autograft bone chips or methylmethacrylate

Complications

  • High rate of recurrence (up to 1/3)
    • Most common locations for recurrence to occur are proximal femur and pelvis
  • Pathologic fractures
    • Very rare
  • Malignant transformation
    • Extremely rare
  • Pulmonary metastases or local invasion are possible, even with “benign” tumors

Prognosis

  • Excellent

chondroblastoma

chondroblastoma

Chondroblastoma. A geographic, lytic lesion is seen in the epiphysis (white and blue arrows) of a skeletally immature (red arrow) male's distal femur. The lesion has a sclerotic margin and is septated. It is confined to the epiphysis. The findings are characteristic of a chondroblastoma, a rare benign bone tumor.
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Wheeless Textbook of Orthopedics

eMedicine  Chondroblastoma: Fines, B and Stacy, G