A lung nodule (or pulmonary nodule) is a descriptive term in medical imaging. Sometimes called “coin lesions,” these small spots or shadows appear in lung images during tests such as CT scans.
A lung nodule is a round or irregularly shaped tissue mass within the lung. They’re typically less than 1.2 inches (30 mm) in diameter, with most under 10 mm. Spots larger than 30 mm are considered lung masses, which carry a higher risk of being cancerous.
Lung nodules are common—about 50% of adults have one or more. They’re often found incidentally during imaging tests for unrelated conditions. Advances in imaging technology have increased detection rates.
Due to their small size, lung nodules rarely cause noticeable symptoms. When symptoms like coughing or wheezing occur, they’re usually unrelated to the nodule itself.
Only in rare cases—when a nodule grows large enough to press on airways or is cancerous—can it cause symptoms. These commonly include coughing, wheezing,and shortness of breath. People may also experience chest or back pain, unexplained weight loss, or coughing up blood.
Lung nodules are categorized by density into three types:
- Non-solid (pure ground glass)
- Part-solid (mixed ground glass)
- Solid
Most lung nodules (about 95%) are non-cancerous (benign). They can result from:
- Abnormal growths
- Infections or scar tissue
- Inflammation or tuberculosis
- Fibrosis
However, a small percentage are cancerous (malignant), particularly in older individuals and heavy smokers. If cancerous, they’re usually early-stage. Early detection makes successful treatment more likely—so don’t panic if you’re diagnosed with a lung nodule!