The most likely diagnosis if you have a lung mass is lung cancer. Yet there are many non-cancerous causes, as noted above. A lung mass is more likely to be cancerous if it is described as “ground glass” on an imaging report, whereas the finding of “calcifications” is more common in benign tumors. If a tumor is described as “cavitary” it is also more likely to be benign. A history of smoking, or working in occupations with exposures to cancer causing substances raises the chances that a tumor is cancer.