Cavitary lung lesion

Differential Diagnosis

Immunocompetent

• Infectious
  • Necrotizing infections
    • Bacterial lung abscess
      • Common bacteria: anaerobes ± aerobic or microaerophilic streptococci
      • Other bacteria: Staphylococcus aureus, Klebsiella pneumoniae, Enterobacterales, Pseudomonas aeruginosa, Legionella species, Haemophilus influenzae type B, Nocardia species, Actinomyces species, Burkholderia pseudomallei
    • Mycobacteria: Mycobacterium tuberculosis, non-tuberculous mycobacteria
    • Fungi: Aspergillus species, Coccidioides species, Histoplasma species, Blastomyces dermatitidis, Cryptococcus species, Mucorales, Pneumocystis jirovecii
    • Parasites: Entamoeba histolytica, Paragonimus westermani
  • Empyema with air-fluid level (i.e. hydropneumothorax)
  • Septic pulmonary emboli
• Non-infectious
  • Pulmonary embolism with infarction
  • Vasculitis, including granulomatosis with polyangiitis
  • Neoplasm
  • Pulmonary sequestration
  • Bullae or cysts with air-fluid level
  • Bronchiectasis
  • Cryptogenic organizing pneumonia
  • Sarcoidosis
  • Rheumatoid nodules
  • Pulmonary Langerhans histiocytosis
  • Foreign body aspiration

Immunocompromised Hosts

• Common
  • Bacteria: Pseudomonas aeruginosa, Enterobacterales, Nocardia species, anaerobes and microaerophilic streptococci, Staphylococcus aureus
  • Mycobacteria: Mycobacterium tuberculosis, Mycobacterium kansasii
  • Fungi: Cryptococcus species, Aspergillus species, Histoplasma capsulatum
• Less common
  • Bacteria: Rhodococcus equi, Legionella species
  • Mycobacteria: Mycobacterium avium complex, non-tuberculous mycobacteria
  • Fungi: Mucorales, Blastomyces dermatitidis, Pneumocystis jirovecii