What Is a Lung Nodule?
A lung nodule, also referred to as a pulmonary nodule, is a mass of tissue located in the lungs. Most lung nodules are benign or non-cancerous, but large masses can be signs of cancer. Symptoms of lung nodules are subtle and may include a tight feeling in the chest, making it easily confused with the flu or a chest cold.
Non-cancerous lung nodules can be caused by a variety of conditions that affect the lungs. Tuberculosis, an infection caused by Mycobacterium tuberculosis bacteria, often spreads to the lungs and forms lung nodules. Histoplasmosis, an infection caused by inhalation of the Histoplasma capsulatum fungus found in certain bat and bird droppings, may attack the lungs and cause nodules. Benign lung nodules can also be caused by blood vessel abnormalities.
To determine if a lung nodule is benign or cancerous, a doctor generally takes a chest X-ray or computerized tomography (CT) scan. If lung nodules are present, they appear on the scan as white, circular shadows. Nodules that are less than 1 inch (25 millimeters) are typically non-cancerous, so a doctor may request a future X-ray or CT scan to ensure the nodules do not grow. If a lung nodule is larger than 1 inch (25 millimeters), further testing will be done to screen for lung cancer.
A biopsy may be performed to retrieve cell samples from the lung tissue for microscopic examination. A doctor may choose to surgically collect the sample by making an incision in the chest and collecting a small piece of lung tissue. Alternatively, a lighted viewing instrument called a bronchoscope can be inserted through the nose or mouth so a doctor can collect the tissue sample in an outpatient setting. Once a sample of the lung nodule is collected, it is sent to a pathologist, a medical professional who is trained to identify disease cells under a microscope.
Benign lung nodules do not generally require any treatment. If the masses are caused by an infection or other condition, they will subside once the other conditions are treated. A doctor may continue to perform regular chest X-rays or CT scans to ensure the nodules do not remain.
If a lung nodule is determined to be cancerous, it can be surgically removed if the cancer cells are found in the lungs only. Lung cancer that is not discovered in the early stages may spread to other internal organs and usually cannot be completely removed through surgery. Radiation or chemotherapy will often be prescribed to treat advanced cancerous lung nodules.
Written by Allison Boelcke
