Lung nodules and interstitial lung disease
A lung nodule is a small round spot seen on a lung scan, most often benign, and follow-up is set by the doctor. Interstitial lung diseases are a group of conditions that thicken or scar the tissue around the air sacs. This page explains what each means, how the assessment goes and what to do.
What is a lung nodule?
A lung nodule (also called a spot or a shadow) is a small round or oval piece of tissue in the lung that shows up on a scan. Cambridge says nodules are usually smaller than one centimetre, can be single or multiple, and are common. They usually cause no symptoms and are found by chance on an X-ray or CT scan taken for another reason.
Most nodules are benign. Cambridge puts about 90 percent as non-cancerous. The AAFP gives the most common benign cause as an “infectious granuloma”, a cluster of immune cells that remains after the body has dealt with an infection. Inflammation or an earlier pneumonia may also leave a nodule in part of the lung (Cambridge).
Some nodules, though, can be malignant or become so later. Cambridge and the AAFP regard smoking (current or past), age over 50, exposure to asbestos and a history of another cancer as raising the risk. That is why a doctor does not leave a nodule alone but follows it up.
What are interstitial lung diseases?
NHLBI says interstitial lung diseases (ILD) are “a group of several disorders” that can cause scarring in the lungs. Scarred tissue becomes thick and stiff, so it is harder for oxygen to reach the blood and for carbon dioxide to leave it. The ALA describes ILD as an umbrella term for many diseases that affect the tissue around the air sacs.
Symptoms (NHLBI and the ALA): breathlessness, a dry cough, discomfort in the chest and great tiredness. The ALA says symptoms are mild at first and may get worse over months or years. In IPF the fingertips can become club-shaped (NHS).
Causes: exposure to dust and mould, work in dusty places, some medicines, autoimmune diseases, smoking, and sometimes genetics. NHLBI and the ALA both say that in some cases no cause is found. The most common type with no known cause is idiopathic pulmonary fibrosis (IPF), which the NHS says usually appears over the age of 70, starts slowly and has an unknown cause.
Who should be seen?
- Someone whose CT or X-ray report contains the words “nodule”, “nodular”, “ground glass” or “fibrosis”, or who has been told to “follow up”. See the article “Words in a CT report”.
- Someone with constant breathlessness or a dry cough that has gone on for weeks or months.
- Someone who has been in contact with dust, mould or chemicals at work or at home.
- Someone with an autoimmune disease or a new medicine who has developed new breathlessness.
How is it assessed?
Nodule:
- The doctor compares earlier and current images to see whether the nodule is new or has grown (AAFP).
- Repeat CT scans: Cambridge says a nodule is monitored with repeated CT scans at intervals, and the time of the next scan is set by specialists based on the result and risk factors. Different sources give this interval as anything from a few months to a year, and the whole monitoring period as one to four years; these are examples, not your plan.
- PET scan if needed for a closer look at the nodule, and biopsy if the nodule grows or looks suspicious (Cambridge and the AAFP). Cambridge says nodules are often too small to biopsy, and if it becomes necessary it is done with CT guidance after it has been explained to you.
- Lung function tests and blood tests in some cases.
Interstitial disease:
- NHLBI says the diagnosis rests on history and lung tests. The ALA names several steps: an examination, imaging (X-ray or CT), blood tests, oximetry, lung function and exercise tests, and in some types bronchoscopy or biopsy.
- For IPF the NHS lists spirometry and a chest X-ray, then a CT scan, and bronchoscopy or biopsy only when the cause is not clear.
- None of these is necessarily needed in your case. They are described in general terms. See the guide “Lung tests and imaging”.
What does treatment generally look like?
Nodule: if it is probably benign, usually only monitoring with CT scans. If it grows or looks suspicious, referral to a lung or cancer specialist and, if needed, a biopsy (AAFP). The type of treatment depends on the result and is for your doctor to decide. The follow-up timing is set by your doctor; do not change it.
Interstitial disease: NHLBI says treatment depends on the type and severity; treatment does not reverse scarring in the lungs, but early treatment can slow or stop further damage. The ALA mentions anti-inflammatory medicines such as steroids for inflammatory or autoimmune types, anti-fibrotic medicines in IPF, oxygen if blood oxygen is low, and lung transplant in severe cases. Pulmonary rehabilitation, stopping smoking, exercise and vaccines are also part of care. If you take steroid tablets, do not stop them on your own (NHS).
What can you do yourself?
- Have your CT scans and appointments as planned, even if you feel well (Cambridge).
- Keep the films and reports of all your earlier imaging and your spirometry reports, and bring them with you.
- Stop smoking cigarettes and hookah. The NHS helps with stopping. Hookah is not harmless.
- Prepare a list of your workplaces, mould in your home and your medicines. Your doctor needs it to look for the cause.
- Ask about recommended vaccines (such as flu and pneumococcal) (NHS for IPF).
- Note down any new symptoms and tell your doctor.
When to get urgent help
- Call 115 (Iran’s emergency number) if you cannot finish a sentence, your lips or nails have turned blue, you suddenly feel confused, you are coughing up a lot of blood or you have sudden breathlessness with chest pain.
- Be seen the same day if you have a few streaks of blood in your phlegm, or your breathlessness is getting worse, or you have a fever with breathlessness.
- Between visits, tell your doctor about a new cough, more breathlessness, or chest or shoulder pain (Cambridge).
- If you cannot reach your doctor, go to the emergency department of the nearest hospital.
See the full list in the guide “When to call urgently”.
Frequently asked questions
Does a lung nodule mean cancer?
No. Cambridge University Hospitals says about 90 percent of lung nodules are not cancer, and the AAFP says most nodules are benign, the most common benign cause being an infectious granuloma, the mark left by an old infection. Some nodules may be malignant, and that is the reason for follow-up. Which group your nodule falls in is for your doctor to say, based on its size, shape, your smoking history and your age.
Why does my doctor say to repeat the CT scan in a few months?
To see whether the nodule has grown. Cambridge says a nodule that has not grown over one to two years is usually benign, and the AAFP says that if a nodule is probably benign, repeat CT scans are done a few months apart (for example three, six or twelve months). Your doctor sets the intervals based on your situation; do not change the timing yourself.
I was told I have a nodule and I am frightened. What should I do until the next CT?
Do not miss the CT scans and appointments in your doctor's plan. If you develop a cough, coughing up blood, breathlessness, or pain in the chest or shoulder, tell your doctor between visits too (Cambridge). If you smoke cigarettes or hookah, stopping helps. Fear is natural; ask your doctor what you are waiting to see.
Should I bring my old X-rays and CT scans?
Yes. The AAFP says the doctor compares earlier images with new ones to see whether the nodule was there before or has grown. Bring the films and reports of all your earlier imaging.
What does "interstitial" or lung fibrosis mean? Is it cancer?
No. NHLBI says interstitial diseases are a group of disorders that can cause scarring in the lungs and stiffen the tissue. They are not cancer. The ALA describes them as a group of diseases that cause inflammation or scarring of the tissue around the air sacs. The type and cause are found through a specialist assessment.
What tests are needed for an interstitial lung disease?
NHLBI says the diagnosis rests on medical and family history and lung tests. The ALA describes several steps: an examination, imaging such as X-ray or CT, blood tests, lung function and exercise tests, and in some types bronchoscopy or a lung biopsy. Not all of these are needed. Your doctor chooses based on your situation.