What are calcium deposits on the lungs?

Usually granulomas: Calcifications seen on chest chest xray are common - often old granulomas, or lymph nodes that were involved in an infection long in the past, that have become calcified over time. Commonly this is from minor histoplasmosis infections. Other causes can be certain tumors of the pleura with calcification of the lining of the lung, or TB with calcifications seen at the apex of the lung.

Old infection?: This can happen after an infection. Most commonly, histoplasmosis, which can be asymptomatic. The calcifications occur after infection is gone. Old tuberculosis can have calcifications as well. The lining of the lung (pleura) can also have calcifications (plaques) from asbestos exposure.