I hear patients often say they have a spot in their lungs. While radiologists do not use the word spot to describe an abnormality in the lung, this term is easily recognized by non medical people as an abnormality of the lung. The terms spot certainly says nothing about what the spot is, how big it is, whether it’s been there for a month or 20 years. It also doesn’t indicate whether it needs to be treated or poses a risk to health. A lot more information is needed to tell what exactly the spot is.
The most concerning abnormality a spot in the lung can be is lung cancer. This will look like a white spot amidst the dark of the lung. The spot can have shaggy or irregular borders. If a prior chest X-ray is available, the spot will usually be larger or new. Lung cancer can be a tiny pinpoint dot or a huge mass occupying a big chunk of the lung. A lung cancer is definitely not diagnosed on a chest X-ray. More testing will be needed. A lung cancer can overlap with the appearance of other abnormalities as well.
Other spots can be old infection called granulomas. These are common calcified or very white dense spots that result from prior infections of the lung. These are benign and pose no threat. Sometimes it is difficult to tell if the spot is calcified or not so more testing may be needed with a CT.
Other spots can represent a small pneumonia or infection of the lung. These are usually not round and defined like spots which are from cancer or granulomas described above, but there is some overlap. You will have cough, fever and other symptoms of a respiratory infection. There are many other causes of spots in the lung which are described in my other articles in the chest section.
Often it is difficult to make a precise diagnosis of what a spot is on chest X-ray. Further testing with a chest CT will be needed. If you have old X-rays, then bring them in because they can be extremely helpful for the radiologist. The idea is that if a spot has been there for years and not changing, then it is something benign. This may save you from further testing and treatment.