What do we know about ground-glass opacity nodules in the lung?

Ground-glass opacity nodules (GGNs) in the lung attract clinical attention owing to their increasing incidence, unique natural course, and association with lung adenocarcinoma. A long and indolent course of a GGN makes it difficult to manage. Current extensive clinical, radiological, pathological, and genetic studies on GGNs have shed light on their pathogenesis and allowed development of a reliable strategy of management. The present editorial provides answers to clinical questions related to GGNs, such as the natural course, follow-up, prediction of growth, and resection techniques. Finally, I discuss the etiology of GGNs, which has not been fully elucidated so far.