Calvarial Hyperostotic Syndrome

• Idiopathic hyperostosis in calvaria of young male Bullmastiffs
• 5-10mths old, male
• Similar to craniomandibular osteopathy (CMO)
• Progressive and often assymetrical skull bone formation
• Grossly:
  • Trabeceulae of the calvarial diploe are thickened and contiguous with a sunburst-like pattern of subperiosteal trabeculae composed of woven and lamellar bone
  • Considerable remodeling (contrast with CMO – where there is rarely much remodeling of the woven bone to lamellar cortical bone)
• Histologically:
  • Mild inflammation (mainly neutrophils)
  • Loose fibrovascular connective tissue supporting stroma
• May be familial, ?sex linked