What is the most common radiographic appearance of a lung abscess?

• A. Cavitation
• B. Pleural thickening
• C. Hilar mass
• D. Hyperinflation

Answer: (A)

The key idea is that a lung abscess most characteristically forms a cavitating lesion on chest imaging. This means you see a rounded or oval cavity within an area of surrounding consolidation, with a thick, irregular wall and often an air-fluid level inside the cavity. The cavity arises from necrotizing infection that destroys lung parenchyma, creating a space that fills with pus and air. This cavitation is what distinguishes an abscess from other infectious or mass-like processes.

Other findings can occur with lung infection, but they don’t define an abscess. Pleural thickening can accompany infection or inflammation, but it isn’t the central feature of an abscess. A hilar mass would suggest a tumor, not an abscess, and hyperinflation points to obstructive processes or chronic lung disease rather than cavitation from an abscess. Remember, early in the disease you might see focal consolidation before cavitation develops, and CT can be more sensitive for detecting cavities.