Pulmonary nodules are small growths in the lung that are oval or round in shape, according to The Cleveland Clinic. Pulmonary nodules, otherwise known as coin lesions or spots on the lung, are generally not any larger than a diameter of 3 centimeters. Anything larger is known as a pulmonary mass, and is more likely to be cancerous.
Pulmonary nodules can be either benign (noncancerous) or malignant (cancerous). Ninety percent of those smaller than a diameter of 2 centimeters are noncancerous. There are several causes for benign pulmonary nodules. Inflammation caused by infection or disease account for many. Nodules also sometimes appear when scar tissue forms as a result of a previous inflammation. Benign nodules can also be the result of noninfectious causes, such as sarcoidosis, rheumatoid arthritis and Wegener's granulomatosis.
Usually patients with pulmonary nodules have no symptoms. In some cases, the patient may develop a cough or cough up blood if the nodules are cancerous. The nodules are typically not discovered until a computed tomography scan or x-ray is taken.
Pulmonary nodules, if benign, are generally not treated. Any treatment involved would be in response to an infection or inflammation that caused the nodules. Cancerous pulmonary nodules are usually surgically removed if the cancer has not spread and the patient is healthy.