A mass on chest x ray is a white spot that is greater than 3 centimeters in size. A mass replaces the normal air filled lung which is dark on an x ray. A mass can press on structures in the chest, cause breathing problems and produce a cough that produces blood.
The main concern with a mass in the lung on chest x-ray is that cancer is present. However, there are other causes of a mass on x ray such as a pneumonia, abscess, lung collapse, and abnormalities with which you are born with. A chest x ray shows that there is an abnormality but a specific diagnosis can not be made in many cases. If there are old studies showing it hasn’t changed, then this suggests it may not be cancerous.
When a chest x ray shows a mass, the next step often involves a chest CT. This will help look closer and determine what the cause may be. If the mass looks suspicious, a biopsy or a PET Scan may be recommended, At other times, it may not be so clear, as a pneumonia can also have this appearance. In this case, another follow up study may be recommended in several months.
When a mass in a lung is diagnosed and is suspicious for cancer, often a biopsy will be needed to determine the exact cause. If it is cancerous, then determining if the cancer has spread becomes important. This can be done with CTs of the rest of the body and PET scans. If the mass is not cancerous, follow up may still be indicated to make sure it does not grow. When your mass turns out to be a pneumonia, it often gets smaller as the pneumonia is treated. The mass will have to be followed until it goes away to be safe. In all cases, you will need to follow the instructions of your doctor closely and get follow ups as needed.