|C||Cancer (squamous cell carcinoma, melanoma, sarcoma mets)|
|A||Autoimmune (Wegener's granulomatosis, rheumatoid lung)|
|V||Vascular (ie bland or septic emboli)|
|I||Infection (TB, fungal (coccidioidomycosis, aspergillosis), bacterial (Staph, strep, Klebsiella))|
|Y||Youth (ie congenital: bronchogenic cyst, sequestration)|
To help narrow your differential diagnosis, consider the thickness of the cavity's wall. If the thickness is greater than 10 mm, this favors a metastatic process; thinner walls are more likely to be secondary to the other causes, with infection being the most common.
|Cavitary disease in pulmonary TB|