With the advancement and widespread use of CT, incidental findings of lung nodules are common. Lung nodules have many causes, most of which are benign such as malignancies, infections, and a few are lung cancer or metastatic cancer. History of smoking, previous history of cancer, sclerosis and nodular disease, chronic obstructive pulmonary disease (COPD), and family history of lung cancer in first-degree relatives also increase the risk of lung cancer. Clinical procedure: The appropriate screening method for nodules smaller than 8 mm and sub-centimeters is still being explored. Although these nodules are less likely to be malignant, they are not easily biopsied and are not well characterized by PET scan. Although the risk of radiation exposure and cost are high, the Fleishner Society recommends screening patients according to their risk of lung cancer when a number of factors are taken into account. The first step in the evaluation of a solid solitary (or predominantly solitary) nodule larger than 8 mm is to assess the likelihood of cancer, followed by an assessment of surgical risk, and patient preference for treatment should also be considered. Next treatment options include CT follow-up, diagnostic testing, and surgical resection. If the patient is at high risk for surgery, a non-surgical biopsy should be considered. If the nodule is benign, treatment is appropriate. There are no standard practice criteria for CT follow-up. If the nodule is malignant, either minor surgical resection or palliative treatment is feasible. At any point in time during CT follow-up, biopsy or surgical resection is indicated whenever there is evidence of nodule growth, unless contraindications exist. Pulverized nodules (subsolid nodules), both pure GGN and partial GGN (50% solid) are highly likely to be precancerous or malignant lesions and are slow growing. In patients with multiple nodules, follow-up needs to be based on the largest nodule. Nodular disease is a multisystem disease characterized by non-caseating epithelioid granulomas, which can involve almost any organ. Thoracic involvement is common and accounts for most of the morbidity and mortality of the disease. At some stage of nodular disease approximately 90% of patients may present with abnormal chest radiographs, and an estimated 20% progress to chronic lung disease leading to pulmonary fibrosis. Although plain radiographs of the chest are the imaging method of choice in cases of lung involvement, CT is more sensitive in detecting enlarged lymph nodes and subtle lesions. Pulmonary nodular disease can present with a variety of radiographic manifestations: bilateral hilar lymph node enlargement is the most commonly seen, followed by interstitial lung disease. The most typical manifestations of pulmonary involvement on HRCT are micronodules along the perilymphatic distribution, fibrotic changes and hyperdensity in the bilateral perihilar region. Atypical manifestations include mass-like or alveolar dense shadows, honeycomb cysts, corn-like dense shadows, mosaic density, tracheobronchial involvement and pleural lesions. Complications, such as varicose veins, may also be seen. Recognition of the typical and atypical radiological manifestations of the disease is essential if timely diagnosis and reduced morbidity and mortality are to be obtained. Capturing the features suggestive of nodular disease and comparing them with pathologic findings can help narrow the differential diagnosis.