Hypertrophic Osteopathy

• Also called hypertrophic pulmonary osteopathy
• In all species
• Associated with chronic lesions (intrathoracic neoplasm or space-occupying lesion) usually in the thorax
  • Tuberculosis
  • Pulmonary neoplasia
  • Granulomatous pleuritis
  • Granulomatous lymphadenitis of mediastinal nodes
• Grossly:
  • Periosteal proliferation of bone on diaphyses of distal limbs
  • Progressive and bilateral
• Histologically:
  • Hyperaemia of periosteum
  • Deposition of new bone
  • Width of cortex may double in a few weeks
• Postulated to be due to stimulation of vagus by intrathoracic lesion -> increasing blood floow to extremities -> thickening of periosteum