Interstitial lung disease: Elementary lesions and diagnosis

An effective approach to the diagnosis of interstitial lung diseases requires a standardized method of evaluation with a structured analysis, beginning with scanning microscopy and proceeding to a more detailed assessment. This article is structured around the histologic patterns defined by Leslie that facilitate this process. They include acute injury, fibrosis, cellular infiltrates, airspace filling, formation of nodules, and minimal changes. Illustrations of all of these patterns are provided, together with a discussion of the disease entities that manifest them.