Lung Cancer Screening: What is a Nodule?

A pulmonary nodule is that dreaded “spot” seen on a Chest CT scan and could mean anything from an old scar to lung cancer. They are typically less than 3 cm in diameter (about 1 1/4th inches). Spots greater than 3cm (1 1/4th inch) are considered masses and are included in the category of findings that require urgent evaluation. 

Nodules are characterized based on how they look. Ground Glass Opacities, nicknamed GGOs, are hazy structures with borders that are difficult to define. Solid nodules are firm structures with clear borders. Semi-solid nodules have characteristics of both solid and GGOs. Completely calcified nodules are not worrisome. Calcified nodules are extremely dense and mean the nodule has been there so long, they’ve basically turned to stone. It is difficult to make a final diagnosis on the basis of the Chest CT alone and consultation with a pulmonologist (doctor who specializes in lungs) can help.