Pulmonary nodular disease is not lung cancer. It is a systemic granulomatous disease of unknown etiology that can involve multiple organs throughout the body. Over 90% of patients will have multiple nodules in their lungs, and chest radiographs will show symmetrical lymph node enlargement in the hilum and mediastinum bilaterally, with or without reticular, nodular or lamellar shadows in the lungs.
Lung cancer, on the other hand, is a malignant neoplastic cellular lesion originating from the bronchial mucosa or glands within the lungs, and a chest x-ray showing S-shaped inverted shadows suggests a central lung cancer.