A lung nodule is a small area of dense tissue in the lung, appearing as a white spot on imaging tests like a chest X-ray or CT scan. This article clarifies what lung nodules are and the considerations involved when one is found.
What Exactly is a Lung Nodule?
A lung nodule, also known as a pulmonary nodule, is a small, round or oval-shaped growth in the lung. These nodules are frequently found incidentally during imaging scans performed for unrelated health concerns. They are distinct from larger lung masses, which are defined as growths exceeding 3 centimeters (about 1.2 inches) in diameter. Approximately 95% of lung nodules are not cancerous. While abnormal, they usually do not cause any symptoms due to their small size.
Interpreting Nodule Size
The size of a lung nodule is an important characteristic, but not the sole determinant of its significance. A 2-centimeter (20 millimeter) lung nodule is considered a medium to large nodule. Lesions larger than 8 millimeters often warrant closer evaluation due to an increased likelihood of malignancy compared to smaller nodules. While smaller nodules, under 6 millimeters, have a very low probability of being cancerous (approximately 1%), a 2 cm nodule requires more attention.
Beyond size, medical professionals assess other features, including the nodule’s shape, density (solid, partly solid, or ground-glass), and any changes over time. The patient’s medical history, including risk factors for lung disease or cancer, also plays a significant role in interpreting a nodule’s potential implications.
Common Reasons for Nodule Formation
Lung nodules can develop for various reasons, with most being non-cancerous. Common benign causes include inflammation from infections like pneumonia, tuberculosis, or fungal infections. Old scars from previous infections or injuries can also appear as nodules on imaging. Inflammatory conditions such as rheumatoid arthritis or sarcoidosis can also form benign nodules. Less commonly, a lung nodule might be a primary lung cancer originating in the lung, or it could represent cancer that has spread from another part of the body.
Next Steps After Nodule Discovery
After a lung nodule is discovered, particularly one measuring 2 cm, the next step involves a thorough consultation with a physician to review the imaging and the patient’s overall health history. The approach to monitoring and managing a nodule is highly individualized. Often, the initial strategy involves watchful waiting, with repeat CT scans scheduled to observe if the nodule changes in size or appearance over time. The timing of these follow-up scans can vary, with more frequent monitoring (e.g., every 3 to 6 months) often recommended for larger or more suspicious nodules.
If the nodule exhibits concerning features, like rapid growth or an irregular shape, further diagnostic tests may be recommended. These can include a PET scan, which helps distinguish between active cancer and benign growths, or a biopsy for tissue examination. In some instances, surgical removal may be considered, especially if there is a high likelihood of malignancy.