What is a pulmonary nodule?

A pulmonary nodule is a spot on the lung that is characterized by a small round or oval shape, according to Cleveland Clinic. Pulmonary nodules are typically smaller than 3 centimeters in diameter. A growth larger than 3 centimeters in diameter is referred to as a pulmonary mass.

Pulmonary nodules can be either malignant or benign, although most are benign and caused by inflammation or disease in the lung. They can be difficult to discover due to the lack of outward symptoms associated with them, and most are found as the result of a chest X-ray or CT scan. While benign nodules do not usually require treatment, malignant ones should be surgically removed, explains Cleveland Clinic.