Interstitial Lung Abnormalities: A Multidisciplinary Narrative Review

Interstitial lung abnormalities (ILAs) is an umbrella term used to describe a spectrum of computed tomography (CT)-detected lung abnormalities that may reflect interstitial lung disease (ILD). Initially perceived as a niche topic-and often underreported in clinical practice-ILAs have gained increasing attention in recent years, given growing evidence of their association with several adverse outcomes, including increased all-cause, respiratory, and cancer-related mortality. Over time, efforts have been made to standardize the definition, classification, and management of ILAs. The recent American Thoracic Society clinical statement has reshaped the definition of ILAs proposed by the Fleischner Society in 2020, introducing substantial changes to the populations in whom ILAs may be identified and proposing new boundaries to distinguish ILAs from ILD. Nevertheless, several key aspects remain debated, and growing efforts are being made to balance the opportunity for early ILD diagnosis against the risk of unnecessary burden on patients and healthcare systems. This is particularly relevant given the increasing number of CT examinations performed in the general population, as well as in patients at increased risk of ILD, such as those with connective tissue disease, and considering the substantial number of examinations related to expanding implementation of lung cancer screening. In this narrative review, we focus on the definition, implications, and management of ILAs, integrating pulmonology, radiology, and pathology perspectives on the strengths and limitations of current approaches.