Granulomas make up about 40% of all SPN (solitary pulmonary nodules). They are seen as round or oval nodules ranging in size from 2mm - 10mm on chest -rays. They may or may not be calcified. The most common cause in the Asian population is tuberculosis while in the western world, histoplasmosis (fungal infection) may be more common.
Granulomas are basically scar tissue from previous inflammation. They do not cause any symptoms and are usually found incidentally on chest radiographs done for some other reason. However, tubercle bacilli may be present and dormant within these granulomas. This may lead to future re-activation.