Unfortunately, the most common cause of a mass in the lungs is one of the types of lung cancer. Lung cancer is the leading cause of cancer deaths in men and women in the United States and can occur even in people who have never smoked. In fact, the majority of people who develop lung cancer at this time do not smoke. The are either former smokers or never smoked -- twenty percent of women who develop lung cancer have never smoked a cigarette. That said, there are benign (non-cancerous) causes of lung masses. Some causes of a lung mass include:
Lung cancer.
Other cancers – Other cancers that may appear as a mass in the lungs include lymphomas and sarcomas.
Benign (non-cancerous) lung tumors – Such as hamartomas.
Metastases (spread) of cancers from other regions of the body to the lung. The most common of these are breast cancer, colon cancer, bladder cancer, and prostate cancer.
Lung abscesses.
AV Malformations - An abnormal connection between arteries and veins that is usually present from birth.
Lipoid pneumonia.
Infections - Fungal infections such as coccidiomycosis and blastomycosis, and parasitic infections such as echinococcus (hydatid cysts).
Pulmonary artery aneurysms – An outpouching in the arteries that travel from the heart to the lungs.
Amyloidosis - A build up of abnormal proteins that forms a mass.