Lung nodules on CT: when they are dangerous and what to do next

You had a CT scan for a cough or before surgery, and the report mentions a "spot" or a "nodule". Many people think the same thing first: is it cancer? Most of the time, no. But you should not ignore it either.

Here we explain what lung nodules are, which types exist, where they come from, how a doctor tells a harmless nodule from a suspicious one and what to do after such a report.

A nodule is a small round shadow in the lung that looks different from the tissue around it. The MSD Manual defines a solitary pulmonary nodule as a spot less than 3 cm across, surrounded on all sides by lung tissue. Doctors call larger growths a mass and assess them differently.

Reports often use "nodule" and "focus" or "spot" as the same thing. Both describe what the scan shows, not a diagnosis. The same goes for the word "growth" or "lesion". It only means there is something in the lung that is not usually there. It can be a scar, a benign tumour or a small patch of old inflammation.

These findings are very common. According to MSD, nodules show up on about 30% of chest CT scans, and most are found by chance when the scan was done for another reason.

The radiologist describes each finding by number, location, density and edges. This decides what happens next.

Single and multiple nodules

A single nodule is assessed on its own: size, shape and change over time. When a report lists many nodules, the picture is different. It is often the result of past infections or inflammatory disease. Less often, it means cancer has spread from another organ. Multiple nodules are always judged together with your history: past cancer, tuberculosis, dust at work.

Solid, part-solid and ground-glass

By density, nodules fall into three types. A solid nodule is dense and fully blocks what lies behind it. A ground-glass nodule looks like a light haze with vessels still visible. A part-solid nodule has both features. Cleveland Clinic uses the same grouping.

Small solid nodules in people without risk factors are almost always harmless. Ground-glass and part-solid nodules follow different rules. MSD notes that the follow-up plan depends on size, nodule type and your personal risk factors.

Subpleural nodules

Subpleural nodules sit just under the pleura, the thin lining of the lung. Their causes are the same as for other nodules. The word only tells you where the nodule is, not how dangerous it is.

Fibrotic and nonspecific nodules

Fibrotic nodules are patches of scar tissue left after inflammation, tuberculosis or pneumonia. Doctors compare them with old scans, and a spot that has not changed for years is reassuring. A radiologist writes "nonspecific nodules" when the features point neither to a benign nor to a malignant cause. It is not a verdict. It is a signal to compare with older images or repeat the scan.

There are many causes, and most have nothing to do with cancer. Cleveland Clinic lists these main groups:

• granulomas after infections such as tuberculosis or fungal infections, the most common benign type
• granulomas in autoimmune diseases such as sarcoidosis or rheumatoid arthritis
• benign tumours: hamartomas, lipomas, adenomas
• scars from smoking, irritants or chemicals
• lung cancer or cancer that has spread from elsewhere

That is why the person matters as much as the shadow. Your doctor will ask about your age, smoking history, past illnesses and job.

Doctors weigh several signs together. Size matters. According to MSD, the chance of cancer is under 1% for nodules smaller than 6 mm and 1-2% for nodules of 6-8 mm. Stability matters too. A nodule that has not grown for 2 years or more points to a benign cause.

This table sums up data from MSD and Cleveland Clinic. No single sign decides. The same small nodule is judged differently in a long-term smoker and in a young person who has never smoked.

Your doctor reads the same nodule differently depending on who you are. MSD lists older age, current or past smoking and a history of cancer among the factors that raise the chance of cancer. Doctors also consider autoimmune disease, work with asbestos, vinyl chloride or radon, living in areas with high tuberculosis rates, and a weak immune system, for example with HIV.

If you have these risk factors, your doctor will usually choose shorter follow-up intervals and consider a biopsy sooner. Without them, watching the nodule is often enough. Be honest about your smoking history and your job. The plan depends on it.

The opposite extreme also exists: wanting to "cut it out just in case". Biopsies and surgery have risks of their own. For example, MSD notes that a needle biopsy through the chest wall leads to a collapsed lung (pneumothorax) in about 10% of cases. So small, low-risk nodules are watched, not removed.

Do not file the report away, and do not treat yourself. Show it to the doctor who ordered the scan or to a pulmonologist. Bring older CT scans and X-rays if you have them. A comparison often answers the question right away.

Next, there are three paths. The first is watching: a repeat CT after a set time. Cleveland Clinic mentions a follow-up scan in 6 to 12 months, but your doctor sets the exact timing based on the size and type of the nodule. The second is extra tests, such as a PET-CT. The third is a biopsy, when it is important to know exactly what the growth is.

Solid nodules: treat or watch

If a nodule is small and looks benign, it is not treated, only monitored. If it looks suspicious or grows, doctors take a tissue sample. They use bronchoscopy, a needle biopsy through the chest wall or surgery. If a tumour is confirmed, an oncologist and a thoracic surgeon make the plan.

Oberig Clinic offers the full set of tests for this. We perform video bronchoscopy with biopsy, needle biopsy through the chest wall guided by ultrasound or CT, and tissue analysis at our own lab. Surgeons in our thoracic surgery department operate both with open surgery and with minimally invasive VATS through small incisions.

Can a nodule go away on its own?

Yes, if it is caused by inflammation. After pneumonia or another infection, some spots shrink or disappear. That is why doctors often suggest a follow-up scan instead of an immediate biopsy.

Do nodules appear after COVID-19?

After viral pneumonia, the lungs can keep areas of consolidation and small patches of fibrosis. Some of them shrink over time. Your doctor decides if you need a follow-up scan, based on how severe the illness was and any new symptoms.

Can an X-ray show a nodule?

A large one, yes. Small nodules are often missed on X-rays because the ribs and heart hide them. That is why CT is used to check and follow them.

Do lung nodules hurt?

Usually not. Most cause no symptoms at all and are found by chance. Pain, coughing up blood, weight loss or a long-lasting cough are reasons to see a doctor without delay, whatever the report says.

Should I quit smoking if the nodule is benign?

Yes. Smoking raises the risk of lung cancer and affects how your doctor will judge any new findings. Quitting helps at any age.

Which doctor should I see with the report?

Start with a pulmonologist or the doctor who referred you. If the nodule looks suspicious, an oncologist and a thoracic surgeon join the plan.

If your CT report mentions spots or nodules, come to Oberig Clinic with your results and older scans. A pulmonologist will compare the images, assess your risk and suggest a plan: watching, a repeat chest CT scan or a biopsy. Our pulmonologists include Anton Sadomov, PhD, associate professor and physician of the highest category.

Book by phone at +38 044 521 30 03 or online.