These abnormal growths are rarely cancerous. Respiratory illnesses and infections can cause nodules to form in the lungs. Most lung nodules are not a sign of lung cancer and don't require treatment. On X-rays or scans, these growths may look like a shadow or spot on the lung.

What causes nodular density in lung?

Lung nodules are usually caused by scar tissue, a healed infection that may never have made you sick, or some irritant in the air. Sometimes, a nodule can be an early lung cancer.

Is a nodule the same as a tumor?

Tumors that are generally larger than three centimeters (1.2 inches) are called masses. If your tumor is three centimeters or less in diameter, it's commonly called a nodule.