What is a pulmonary nodule?
A pulmonary nodule is a small round or oval-shaped growth in the lung. It is sometimes also called a spot on the lung or a coin lesion. Pulmonary nodules are generally smaller than 3 cm in diameter. If the growth is larger than that, it is known as a pulmonary mass. A mass is more likely to represent a cancer than is a nodule.
What causes pulmonary nodules?
There are two main types of pulmonary nodules: malignant (cancerous) and benign (noncancerous). Over 90% of pulmonary nodules that are smaller than 2 cm in diameter are benign. Benign pulmonary nodules can have a wide variety of causes. Many are the result of inflammation in the lung as a result of an infection or disease producing inflammation in the body. The nodule may represent an active process or be the result of scar tissue formation related to prior inflammation.
How common are pulmonary nodules?
Innumerable pulmonary nodules are discovered each year during chest X-rays or CT scans. Most nodules are noncancerous (benign). A solitary pulmonary nodule is found on up to 0.2% of all chest X-rays films. Lung nodules can be found on up to half of all CT scans of the chest. Risk factors for malignant pulmonary nodules include a history of smoking and older age.