The following CXR shows

Ans. (a) Metastasis to lungs* Metastatic malignant neoplasms are the most common form of secondary lung tumors. Lung metastases are identified in 30-55% of all cancer patients, though prevalence varies based on the type of primary cancer.* Chest radiography (CXR) is the initial imaging modality used in the detection of suspected pulmonary metastasis in patients with known malignancies. Chest CT scanning without contrast is more sensitive than CXR* The most common radiographic pattern of pulmonary metastasis is the presence of multiple nodules, ranging in size from 3 mm to 15 cm or more.* The nodules are more common in the lung bases (owing to higher blood flow than upper lobes) and in the outer third of the lungs in the subpleural region.* They are approximately spherical and of varying sizes. Nodules of same size are believed to originate at the same time, in a single shower of emboli from the primary tumor. Nodules that are smaller than 2 cm are usually round and have smooth margins. Larger nodules are lobulated and have irregular margins; they may become confluent with adjacent nodules, resulting in a conglomerate multinodular mass.