Calcification in the lung results from a lung nodule that has built up calcium around it over time; it is typically caused by lung infections, according to the Beth Israel Lung Nodule Center. Most pulmonary nodules are benign, especially those smaller than 2 centimeters in diameter, explains Cleveland Clinic.
Pulmonary nodules grow in the lung as part of a response to infection, states the Beth Israel Lung Nodule Center. Tuberculosis, for example, can cause nodules and granulomas by inflaming the tissue of the lung. Calcium may build up around the nodules during the healing process of the lung, notes Cleveland Clinic. Rheumatoid arthritis and a few other rare disorders can also cause nodules and granulomas to grow in the lung.
In rare cases, calcified nodules can be cancerous. Usually, the nodules are a sign of lung cancer or they can be tumors that have metastasized from another cancer in the body, says the Beth Israel Lung Nodule Center. Most patients with malignant calcified nodules have a predisposition to lung cancer or engaged in risk factors for the cancer, such as smoking. Exposure to toxic materials might contribute to the growth of malignant nodules in the lungs.
Many patients do not have any symptoms when they have a calcified nodule growth, states Cleveland Clinic. Often, a chest X-ray is the only accurate way to detect the nodules.