Case of the Season: Management of the Subsolid Pulmonary Nodule

Abstract

Introduction Solitary pulmonary nodules, both solid and subsolid, are detected with increasing frequency because of the widespread use of multidetector computed tomography (CT). Knowledge gleaned from lung cancer CT screening trials have contributed to the recent release of guidelines for the management of pulmonary nodules, solid and subsolid, by the Fleischner Society, the National Comprehensive Cancer Network, and the American College of Chest Physicians. In terms of nodule attenuation, a solid nodule completely obscures the lung parenchyma and represents a rounded opacity, well or poorly defined, measuring up to 3 cm in diameter. Additionally, focal pulmonary lesions that are more than 3 cm in diameter are called lungmasses and are presumed to represent lung carcinoma until proven otherwise. By contrast, a subsolid nodule (SSN) is characterized by a hazy increased opacity of the lungwith preservation of bronchial and vascularmargins as visualized on high-resolution CT. SSNs can be classified as pure ground-glass nodules (GGNs) (nonsolid, containing only ground-glass components) or “part-solid” nodules (containing both a solid and ground-glass components). Although most of the nodules are benign owing to such entities as organizing pneumonia, focal fibrosis, and hemorrhage, lung cancer is a clinically important entity in the differential diagnosis of solitary pulmonary nodules. It has been reported that adenocarcinoma in situ and invasive adenocarcinoma of the lung are especially prevalent in partsolid nodules that have a large solid component with more than 50% of ground-glass component. Moreover, larger partsolid nodules aremore likely to bemalignant and invasive than smaller part-solid nodules. Here, we present a “case of the