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Lung Cancer

Pneumonia or mass



My mom went to primecare where we live today and they did a chest x ray which the doctor said showed a large mass on left lung(size of a small lemon he said). He said he could not say if it was cancer because it could be pneumonia, cancer or any possibility. So he scheduled her for a ct scan! I want to ask do lung cancer and pneumonia look similar? I just think that surely the doctor would have no doubt about pneumonia if that is what it is! Right?And if it is cancer of the lung does the size have anything to do with how good or bad? i.e. small size-better diagnoses and large size worse diagnosis? How will they be able to tell if it is cancer and if it has spread to lymph nodes or organs? I`m really worried! Just trying to get reassurance for the unknown at this point. Why couldn`t he just say if he was pretty sure it was cancer or not? Don`t doctors know what cancer looks like even if it is not their specialty? I just do not understand how a ct scan could give anymore a definitive answer than a chest xray unless it was biopsied. What`s really the chance of it being anything other than lung cancer? I just really need to know yes or no! Thanks so much for listening! I`m just really worried! I can`t imagine my world without my mom in it and I`m a grown adult! My mom is only 58, so young!!!!!!!!!!!


Thank you for your question. I understand your worries.

A shadow in the chest CT scan can be from cancer, pneumonia, infection, bleeding, etc. Based on the character of the shadow we can sometimes say either it is most likely a cancer or a pneumonia. But sometimes it is hard to diagnose cancer from just Chest CT. Also, we have to weigh in other factors such as smoking history or any other history of cancer to determine the likelihood of cancer. In these cases we need to get tissue or specimen from the mass to make an accurate diagnosis.

There are several ways we can get a diagnosis:

(1) Bronchoscopy, where a tube with a camera is inserted through the nose or mouth into the airways and based on the location of the mass we can get a biopsy or washings.

(2) Another way to diagnose will be a needle biopsy from outside the chest under CT guidance.

In both the above cases we can obtain tissue for culture as well to rule out infection. However, these tests are not always 100% successful. In other words, a negative test does not completely rule out cancer or infection as a lot of time we may not obtain good tissue with these tests. In these cases we can follow up with another CT scan in 3 months to see if the mass has increased in size. Depending on the rate of increasing size we can guess whether the mass is cancer or infection.

Your physician may refer you to a pulmonary (lung) specialist who may be able to help you understand the process better. However, please let us know if you still have any questions.

For more information:

Go to the Lung Cancer health topic, where you can:

Response by:

Shaheen  Islam, MD, MPH Shaheen Islam, MD, MPH
Clinical Associate Professor
Pulmonary, Allergy, Critical Care & Sleep
College of Medicine
The Ohio State University