Lipid Pneumonia

Lipid pneumonia (Image sourced from Bristol Biomed Image Archive with permission)

• Associated with inhalation of oil, paraffin, etc.
• Reaction dominated by macrophages which fill the alveoli and interstitial thickening (mononuclear cells and fibrosis)
• Tends to acumulate in ventral regions bilterally
• Occurs subclinically in cats, sometimes dogs, unrelated to aspiration
• Gross lesion:
  • Multifocal, firm, white nodules
• Microscopic lesions:
  • Macrophages full of lipid forming foam within alveoli
  • Interstitial lymphocyte and plasma cell infiltration, fibrosis