What Is a Pulmonary Nodule?
A pulmonary or lung nodule is a small, rounded or oval-shaped growth in the lungs. It may be found accidentally during tests such as X-ray or CT (computed tomography) scans. Lung nodules may also be referred to as coin lesions or lung spots. Most lung nodules are benign, and their occurrence may be due to infections, inflammation, or scarring. However, a few may be cancerous, and hence, medical evaluation of lung nodules is necessary.
Pulmonary nodules are lung lesions measuring less than or equal to 3 centimeters or 30 millimeters in diameter. Lung lesions larger than this are known as lung masses. Lung masses have a higher potential to be cancerous (lung cancer).
How to Rule Out Lung Cancer if You Have a Pulmonary Nodule?
As lung nodules are widespread, they could be easily identified in half of the population during their routine chest X-rays and CT scans. In addition, it has been reported that lung nodules are usually benign, except in 5% of the population. Benign pulmonary nodules can result from various factors, including infections and scarring. When healthcare professionals diagnose a pulmonary nodule, they might refer for some additional tests to rule out lung cancer.
What Are the Causes of Pulmonary Nodules?
Pulmonary nodules can develop due to infection or inflammation of the lung tissue, resulting in the clumping of cells into granulomas. Gradually, the granuloma calcifies and hardens within the lung, forming a benign pulmonary nodule.
There are two types of benign pulmonary nodules; they are the following:
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Hamartomas - It is one of the most common types of benign pulmonary nodules. They are composed of abnormal amounts of normal tissues like fat, cartilage, connective tissue, and muscle. They are mostly found on the outer surface of lung connective tissue, with some on the airways leading to the lungs. They do not press against the surrounding tissues and are limited only to the particular area. It is said that hamartomas are more common in males aged 50 to 70 than in females. On chest X-rays, it can rarely appear as fluffy wool or popcorn in addition to the coin-like round growth. These coin-like, round growths on chest X-rays are usually less than three centimeters in diameter.
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Bronchial Adenomas - The other common type of benign pulmonary nodule is bronchial adenoma.
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They grow in the airways of the lungs.
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Mucous glands.
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Ducts of the trachea.
The other causes of benign pulmonary nodules are;
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Air pollutants or irritants.
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Fungal infections (histoplasmosis, coccidioidomycosis, etc.).
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Scar tissues.
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Respiratory system infections like tuberculosis, chronic obstructive pulmonary disease (COPD), etc.
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Autoimmune diseases such as sarcoidosis and rheumatoid arthritis.
Pulmonary nodules can be cancerous, and malignant pulmonary nodules are usually large. Large lung nodules, such as 30 millimeters or more, are more likely to be cancerous. The abnormal growth of cells in the lung is known as a neoplasm.
Some examples of malignant neoplasms are carcinoid tumors and lung cancer, and the benign neoplasms may include neurofibromas. Nodules larger than 8 to 10 mm in size, irregularly shaped, or those that increase in size over time are more likely to require further evaluation.
Who Is at Risk of Developing Pulmonary Nodules?
No specific population group is at a higher risk of developing pulmonary nodules. However, the following factors will increase the risk of a pulmonary nodule getting converted into cancer.
They are:
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Elderly people.
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Having a larger nodule.
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Previous or current smokers.
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Family history of cancer.
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Handling asbestos in the past.
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Had exposure to radon or other secondhand smoke.
What Are the Signs and Symptoms of Pulmonary Nodules?
Benign pulmonary nodules do not cause symptoms and usually do not extend beyond the surrounding tissues. In the case of large or cancerous nodules, the tissue growth may press against the airway, resulting in cough, wheezing, and difficulty breathing. Over time, the person may develop the signs of early-stage lung cancer, like:
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Discomfort in the chest.
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Coughing up blood.
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Wheezing.
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Tiredness.
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Hoarseness of voice.
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Loss of appetite.
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Sudden, unexplained weight loss.
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Recurring respiratory infections such as bronchitis or pneumonia.
Consult the doctor when you have pulmonary nodules and experience the above-mentioned symptoms.
How Are Pulmonary Nodules Diagnosed?
Lung nodules may be identified during an imaging test performed for another purpose or while preparing for other procedures. If you have a lung nodule, you might be placed on active surveillance and asked to have another CT scan after 6 to 12 months.
During the 2-year surveillance, if the nodule remains unchanged, it is unlikely to become cancerous, and you can stop CT scans. If the nodule enlarges and becomes 13 millimeters or more, the doctor may advise further tests.
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Bronchoscopy: The healthcare provider will sedate the patient and insert a bronchoscope through the mouth and into the lungs. This instrument helps cut a tissue sample from the nodule. The retrieved tissue sample is sent to the laboratory to analyze the presence of abnormal cells.
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CT Scan-Guided Biopsy: If the pulmonary nodule is located in the outer part of the lung, a CT scan-guided biopsy might be needed. The physician might use the CT images to guide a thin needle into the lung. The tissue taken for biopsy with a thin needle is sent to the laboratory, where it is examined for abnormal cells.
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Positron Emission Tomography Scan (PET): An imaging device and an injectable radioactive tracer are used to detect diseased cells in the lungs.
Recent Updates in the Diagnosis of Pulmonary Nodules
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Low-dose CT scans are advised for high-risk patients, especially smokers between the ages of 50 and 80.
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Guidelines for patient follow-up are now risk-based, thereby reducing unnecessary scans.
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Biopsy procedures are becoming more minimally invasive, increasing the accuracy and reducing the complications.
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Artificial intelligence-based imaging systems are being employed to detect suspicious nodules at early stages and monitor their growth.
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Individualized approaches to patient evaluation are helping to determine the need for biopsy.
What Are the Treatment Options for Pulmonary Nodules?
Usually, non-cancerous pulmonary nodules do not require treatment. If you have an infection or inflammation, you may need medications, such as:
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Antibiotics.
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Antifungals.
Surgical treatment is required when the pulmonary nodule turns cancerous or causes trouble. The surgical procedures carried out in patients with cancerous and non-cancerous pulmonary nodules are:
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Video-Assisted Thoracic Surgery (VATS): At the time of the procedure, small instruments and a thoracoscope are inserted through the small incisions. A thoracoscope is a camera that the physician uses to view the images and remove the nodule.
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Thoracotomy: The surgeon might extract the pulmonary nodule by thoracotomy, that is, below the shoulder blade and between the ribs to reach the lungs. After surgery, a tube drains excess fluid from your chest for several days.
Conclusion:
Pulmonary nodules are not always cancerous. Malignant and sometimes non-cancerous pulmonary nodules may press against the airway and cause complete or partial blockage in some people. In these cases, surgery might be required to clear the pathway for better breathing. Avoid or reduce cigarette smoking, exposure to irritants, and asbestosis to protect the lungs from pulmonary nodules. When you experience any abnormal symptoms, do not hesitate to consult a lung specialist for evaluation and advice.
Key Takeaways:
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Pulmonary nodules are very common and mostly benign.
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Nodules are often found by accident on CT scans.
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Shape, size, and rate of increase help predict cancer risk.
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Smoking and older age increase the risk of cancer.
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Many pulmonary nodules are monitored with routine checkups.
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Prompt investigation is important for obtaining an accurate diagnosis.
