LAUSR

We read with interest the article by Culver and colleagues (1) describing the relevance, use, and attributes of idiopathic pulmonary fibrosis (IPF) patient registries and the subsequent correspondence by Nett and colleagues (2), who rightly point out the added importance of collecting environmental and occupational exposure data. In addition to acknowledging the utility of such data collection, Culver and Kim, in their reply (3) to Nett and colleagues, also emphasize the hurdles in the evaluation of a proper environmental/occupational history. On the basis of our environmental pathology experience, we want to bring up the importance of histologic evaluation in independently supplementing and confirming the environmental/occupational investigation in cases of interstitial lung disease in general and IPF in particular. Light microscopic evaluation and characterization of dust burden is an easy and underused tool in the hands of pathologists, whose reports can highlight the presence of dust that differs from background dust accumulation in lungs. Currently, there is no requirement (or even mention) of these minimal additional observations that pathologists can record in the American Thoracic Society/European Respiratory Society guidelines for diagnosis of IPF (4), which suggest only doing an iron stain when there is a positive history of asbestos exposure and ruling out obvious pneumoconiosis. We have seen many lung tissues over the years in which an evident environmental/occupational etiology has been considered neither by the clinician nor by the pathologist, hence misclassifying cases as “idiopathic” (i.e., IPF). We propose at least minimal criteria for dust characterization for pathologists to follow in their evaluation of biopsies in which IPF is within the differential diagnosis: