Bone cysts and cyst-like conditions

• Bone cysts and cyst-like conditions are not true tumours
  • MRI is best for diagnosis
  • Simple bone cyst
    • = serous fluid-filled lesion
    • Usually found in young people
  • Aneurysmal bone cyst (ABC)
    • Shows multiple fluid lines (niveau) on MRI or CT
    • Because it contains multiple liquids of different density
  • Non-ossifying fibroma
    • Due to dysfunctional ossification
    • Located in metaphysis of long bones of the lower extremity
    • Has such a characteristic x-ray appearance that MRI or biopsy is not necessary
      • “Bubbly” lytic lesion with sclerotic outline on x-ray