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Tumour Like Conditions


  • Benign lesion which occurs during growth
  • 20% of benign bone lesions
  • Age 5-15 years
  • Not found in adults
  • Sex male to female is 3:1
  • The most common location is the proximal humerus (67%) followed by the proximal femur (15%)
  • UBC's may be found in unusual sites (e.g. calcaneum, pelvis) in patients >17 years
  • Cysts may be Active or Latent: Active cysts are located near the growth plate, but they move further away as the child grows and become inactive (latent)


  • Asymptomatic
  • Usually presents as a pathological fracture (~ 65%)


  • Unknown
  • Venous obstruction leading to a transudate of fluid  
  • Fluid contains high levels of IL-1 & IL-6, which stimulate osteoclasts

Differential diagnosis

  • Depending on the location,

Radiographic features

  • Well defined, central osteolytic area with a thin sclerotic margin
  • Metaphyseal in young - moves towards diaphysis with growth
  • It fills and slightly expands the juxta epiphyseal metaphysis
  • CT not helpful unless the UBC is in the pelvis



  • Histologically UBC's are thin walled cavities filled with blood tinged fluid.  
  • The lining cells are cuboidal, but are not an endothelium
  • There is endosteal osteoclastic activity and periosteal new bone formation

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Bone Tumours
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Bone Tumours - Diagnosis
Heterotopic Ossification
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Tumour Like Conditions
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