Unusual radiographic manifestations of lung cancer.

The majority of lung cancers present as either a solitary parenchymal nodule or mass or as a hilar mass that demonstrates progressive growth with time. Unusual parenchymal manifestations of lung cancer include a nodule or mass that may decrease in size without therapy; intrinsic calcification; thin-walled cavitation; a meniscus sign; unifocal or multifocal alveolar infiltrates; satellite nodules; and multiple well-defined pulmonary nodules or masses. Unusual bronchial manifestations of lung cancer include widely separated areas of segmental or lobar atelectasis, mucoid impaction of bronchi, and obstructive hyperinflation. In the pleural space, bronchogenic carcinoma may occasionally be manifested as spontaneous pneumothorax, diffuse nodular tumor spread, and isolated effusion. Unusual mediastinal manifestations of lung cancer include primary mediastinal bronchogenic carcinoma, "downhill" esophageal varices, pulmonary artery invasion and infarction, pericardial and cardiac invasion, and esophageal obstruction. In addition, lung cancer may arise as a complication of bullous lung disease and a number of conditions that cause focal or diffuse lung scarring. Through increased familiarity with these varied manifestations of lung cancer, and a high index of suspicion, it is hoped that the radiographic detection of lung cancer will be improved.