How large would a lung mass have to be to show up on a chest x-ray?

By definition. A mass is 3 cm or greater. A nodule is anything smaller. Depending on how good the film is, you can see nodules less than a cm I think....I'm not a radiologist though. CT scan is much better for assessing pathology in the lungs .

Related Questions

I have had a non productive for 2 months. Chest X-ray show 3.8 CM mass on my left lung. My dr. Says its proabaly a shadow. What is a shadow?

Look further. With a cough for that long and a mass that big i would have your doctor look further. A ct scan might be in order. It is possible to be a nipple shadow but i doubt it. I would want more answers to why i still had a cough. Read more...
A bad term. Masses absorb x-rays and cause "shadows" (white areas on an x-ray) the same way your body blocks the sun and causes a dark shadow. A mass is a medical term, a shadow is not. You probably need a chest ct. Read more...
Something. In your lung. It came on fast so may be pneumonia or healing pneumonia. Likely not a cancer, but must be followed until it goes away. Read more...
Do not ignore. The term shadow is sometimes used interchangeably with density in lungs. 3.8 cm mass is usually not nothing. You should probably have CT exam of chest. Maybe you should contact radiologist reading study for exact interpretation. Read more...

What could large dense mass on chest X-ray be?  

Most common. lung masses could be benign or malignant tumors. I urge you to consult your primary doctor as soon as possible. A Chest CT scan (right image) and referral to lung specialist may be ordered. Read more...