A large mass could well be a tumor, and have contributed to pneumonia, but it may not necessarily be a malignant tumor. It could be a benign tumor that is pressing on a bronchial tube and making it hard to cough out mucus and, with mucus build-up, pneumonia could develop.
The first step should be to determine the nature of this mass. That could probably best be done with a bronchoscopy and biopsy. A bronchoscopy is a procedure that is done under local rather than general anesthesia to create conscious sedation, which is like a light sleep. During this procedure a bronchoscope is passed through your nose into your windpipe to look into your lungs. A bronchoscope is a flexible tube with a small camera at one end. With the bronchoscope tiny pieces of lung tissue can be taken for further testing. This is called lung biopsy.
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