Infiltrate on a chest X-ray report is a common finding that radiologists use to describe a white abnormal area of unclear cause. An abnormal area of infiltrate on a chest X-ray can represent many abnormalities such as infection, water or edema, tumor, abnormal inflammation not related to infection, scarring, collapsed lung tissue and other things. An infiltrate is therefore a term used to describe an abnormal area in the lung whose cause is not clear.
An infiltrate on a chest X-ray can be localized to one small area or be throughout both lungs. It often has a poorly defined irregular white appearance superimposed on the black of the lung. While a mass is often defined and round, an infiltrate is usually not.
In my experience, an infiltrate most commonly represents an infection such as a pneumonia. But many other possibilities exist to include cancer. Often the ordering clinical doctor will use the patient’s clinical information along with the x ray to come up with best diagnosis. For example, a patient who has a cough, fever and an infiltrate on chest X-ray will most likely have a pneumonia. Another patient who is a smoker with a chronic cough and an infiltrate on chest X-ray may have cancer.
This emphasizes the importance of combining the radiology results with your clinical history and laboratory testing. In some cases, your doctor may wish to evaluate further with a cat scan of the lungs and perhaps refer you to a specialist. This is particularly true if there are other concerning findings such as round spots or nodules, or enlarged lymph nodes.
An infiltrate on chest X-ray is more of a descriptive term then a diagnosis. Sometimes it’s not possible to state the exact nature of a white area on a chest X-ray as any abnormality that blocks the X-rays from penetrating the lungs will be white. The word infiltrate is then a descriptive term that must be combined with your clinical information, and perhaps more testing.
In some cases, your doctor may simply choose to treat you with antibiotics and see if the infiltrate on chest X-ray will disappear when you get another one after a short time. This assumes you have an infection that will clear with antibiotics. If the repeat chest X-ray shows that the infiltrate has not cleared, then that becomes more concerning. An infection should clear after therapy. This may mean that you have something treatment resistant or a cancer.
Often a chest cat scan will be ordered. This will be more definitive and increase the suspicion for cancer or other abnormality aside from infection. You may be referred to a pulmonologist who will do further testing including biopsy to arrive at the correct diagnosis.
The term infiltrate therefore can be something as benign as some collapsed lung tissue all the way to cancer. It is very important that you discuss this with your doctor to arrive at the best plan going forward. He will use all the information available to give you the best chance of a successful outcome.