A “spot on the lung” typically refers to a pulmonary nodule, a small, abnormal growth visible on imaging tests like X-rays or CT scans. While these findings can be unsettling, lung spots are common, appearing in up to half of all lung CT scans. Most nodules are benign, or non-cancerous. However, any detected lung spot requires medical evaluation to determine its characteristics and origin.
Common Benign Causes
Many lung spots stem from common, non-threatening conditions, often infections. The body’s immune response to pathogens can leave behind scar tissue or granulomas, which are small collections of immune cells. Past bacterial infections, such as pneumonia or tuberculosis, frequently result in these marks. Fungal infections also contribute, particularly where specific fungal spores are common. Pathogens like Histoplasma capsulatum, Coccidioides immitis (causing Valley fever), and Blastomyces dermatiditis can trigger granuloma formation, which may harden through calcification and become more visible on imaging.
Inflammatory conditions, where the immune system mistakenly targets its own tissues, also cause lung nodules. Sarcoidosis, for example, forms tiny inflammatory cell clusters in organs, often affecting the lungs and lymph nodes. Autoimmune diseases like rheumatoid arthritis can similarly induce inflammation that appears as pulmonary nodules.
Even after an infection or inflammatory episode resolves, lung tissue can retain permanent alterations. These often appear as harmless scar tissue or calcified granulomas on imaging scans. Such residual marks are essentially remnants of the body’s healing processes and typically pose no ongoing health risk. These benign nodules usually remain stable in size or may even shrink over extended periods.
Serious Causes Requiring Attention
While most lung spots are benign, some indicate serious underlying conditions requiring prompt medical attention. Lung cancer is a primary concern, often appearing as a solitary nodule. This can be primary lung cancer, originating in the lung, or metastatic cancer, where cells have spread from another tumor. Risk factors for cancerous nodules include smoking history, age over 50 or 60, family history of lung cancer, and exposure to substances like asbestos or radon.
A nodule’s appearance on imaging can provide clues; larger nodules, or those with irregular or spiculated (jagged) edges, are more concerning for malignancy. Early detection is important for better outcomes.
Beyond malignancy, other less common but still significant conditions can cause lung spots. Benign tumors, such as hamartomas, are abnormal but non-cancerous growths of disorganized lung tissues like cartilage, fat, and muscle. Often found incidentally, they can sometimes be diagnosed by specific CT features, such as fat or “popcorn-like” calcifications. Vascular malformations, abnormal connections between blood vessels, can also appear as lung spots. These include pulmonary arteriovenous malformations (PAVMs), which are rare and can cause symptoms like shortness of breath or serious complications.
How Lung Spots Are Investigated
Investigation of a lung spot typically begins with imaging. A chest X-ray often first detects a spot, but a computed tomography (CT) scan provides more detailed information on its size, shape, and characteristics. A positron emission tomography (PET) scan can further assess metabolic activity, helping distinguish benign from cancerous growths.
For low-risk nodules, a “watchful waiting” strategy is employed. This involves scheduled repeat CT scans, usually every few months to a year, to monitor for changes. If a nodule remains stable for about two years, it is highly likely benign and may require no further intervention.
When a nodule is suspicious or grows, a biopsy is necessary to obtain a tissue sample. Methods include CT-guided needle biopsy, using imaging for precise placement, or bronchoscopy, where a flexible tube accesses the airways. In some cases, a surgical biopsy may be performed, especially if other techniques are inconclusive or the nodule is hard to reach.
What to Do Next
If a lung spot is detected or suspected, seek professional medical advice immediately. Self-diagnosis is not appropriate; only a healthcare provider can accurately assess the spot’s nature. Provide a comprehensive medical history, including smoking status, past infections, and relevant family history, as these details influence the diagnostic process and risk assessment.
Adhere to the doctor’s recommendations for follow-up imaging or additional diagnostic tests. Consistent monitoring tracks changes in the nodule, informing subsequent decisions and potentially avoiding unnecessary procedures. Engage with your healthcare team by asking questions about findings, the recommended plan, and potential outcomes. Understanding your situation and participating in decision-making ensures appropriate, personalized care.