Bone Cysts

Bone cysts (Image sourced from Bristol Biomed Image Archive with permission)

• May be seen radiographically
• Must be distinguished from neoplasia
• Expansile lytic masses
• Do not appear aggressive
• Subchondral cysts
  • Common in horses and pigs
  • Usually manifestations of osteochondrosis and DJD
• Simple cysts
  • May contain clear colourless fluid, or serosanguinous
  • Wall of dense fibrous tissue, woven or lamellar bone
• Aneurysmal bone cysts
  • Expansie lesions
  • Arise from disturbance of vascular tissue of bone marrow
  • Grossly:
    • Appear as blood filled sponge
    • Spaces separated by fibrous trabeculae
  • Histologically:
    • Proliferation of undifferentiated mesenchymal cell with multinucleated osteoclast-like cells
    • Haemorrhage and haemosiderosis
• Radiography is essential to help differentiate with cavity of a neoplasm