Asbestosis: demonstration of distinctive interstitial fibroelastosis: a pilot study

Our plain-English summary of Asbestosis: demonstration of distinctive interstitial fibroelastosis: a pilot study, by M.R. Wick, T.J. Kendall, J.H. Ritter (Annals of Diagnostic Pathology, 2009).

The study

• Authors: M.R. Wick, T.J. Kendall, J.H. Ritter
• Journal: Annals of Diagnostic Pathology
• Published: 2009;13(5):297-302
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Asbestosis has long been defined as a diffuse interstitial "fibrotic" process, in similarity to other chronic interstitial pulmonary diseases. To address the hypothesis (which was based on morphological nuances) that the interstitial connective tissue response in asbestosis may be fibroelastotic rather than fibrotic, a comparative characterization of the connective response in cases of asbestosis and other forms of interstitial lung disease was performed. Archival open lung biopsies or autopsy specimens of pulmonary diseases featuring interstitial connective tissue abnormalities (15 of asbestosis, 21 of organizing pneumonia, 15 usual interstitial pneumonitis/idiopathic pulmonary fibrosis [IPF], 9 organizing diffuse alveolar damage, 9 "nonspecific" interstitial pneumonitis, 4 sarcoidosis, 3 each of desquamative interstitial pneumonia and chronic amiodarone toxicity, 2 cryptogenic organizing pneumonias, and 1 each of chronic hypersensitivity pneumonitis and chronic eosinophilic pneumonitis [85 total]) were stained histochemically with hematoxylin and eosin, Perl's method, Gomori's trichrome procedure, and the Verhoeff-van Gieson technique. Representative subsets of the cases (n = 20) were also studied immunohistologically using an antibody to elastin. Fibroelastosis in each of the samples was assessed for the degree of response and its location using a 3-tiered scale. The degree of fibroelastosis in the 15 cases of asbestosis was variable, with the pattern being peribronchial and perivascular in all instances; at least 2 asbestos bodies were identified in fibroelastotic foci in each of the 15 cases as highlighted with Perl's stain. Forty-seven cases of nonasbestotic lung disease (71%) showed interstitial fibrosis with a variable (usually modest) amount of admixed elastic tissue; when present, elastic fibers were distributed in a diffuse interstitial pattern, with or without perivascular accentuation. All cases of IPF also showed areas of fibroelastosis, but those foci were confined to regions of overt "honeycomb" change. No asbestos bodies were seen in any disease except asbestosis, and a predominantly peribronchial pattern of fibroelastosis was not identified in any nonasbestotic interstitial lung disease in this study. The authors conclude that the types and patterns of pulmonary connective tissue response in interstitial lung diseases may provide additional diagnostic clues to the presence of asbestosis.

In plain English

This pilot study by pathologists compared the connective tissue in lung samples from asbestosis with that in other scarring (interstitial) lung diseases. The authors searched their institutions' files from 1987 to 2002 for biopsy and autopsy cases of interstitial lung disease with fibrosis. The results describe 15 asbestosis cases and 70 cases of other diseases, such as organizing pneumonia and usual interstitial pneumonia/idiopathic pulmonary fibrosis. Asbestosis was defined by 1982 College of American Pathologists criteria, which include asbestos bodies in the scarred areas. The article does not report the patients' work histories or fiber types. Samples were stained to show elastic fibers, collagen and iron. In 12 of the 15 asbestosis cases, dense elastic tissue was concentrated around small airways. The other 3, which had early "honeycomb" change, showed a more diffuse pattern. Elastic tissue was seen in 47 of the other cases, but it was diffuse or mainly around blood vessels, with no accentuation around airways. No asbestos bodies were seen in any of the other cases. The authors concluded that their hypothesis was supported and that this pattern may offer additional diagnostic clues to asbestosis.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Pilot study comparing tissue staining patterns in archived lung biopsy and autopsy specimens of asbestosis and other interstitial lung diseases
• Who was studied: Surgical (open wedge lower-lobe biopsy) and autopsy cases of interstitial lung disease with fibrosis from the authors' institutional files, 1987 to 2002. The results describe 15 asbestosis cases and 70 non-asbestosis cases. All patients were adults aged 37 to 78, and all asbestosis patients were men.
• Exposure: Asbestos exposure was not measured or described. Asbestosis was defined histologically by 1982 College of American Pathologists criteria, including at least 2 asbestos bodies in scarred areas. Fiber types and occupational histories are not reported.
• Main results:
  • Asbestosis cases (15): 8 showed scarring only around airways and blood vessels; 4 also had scarring under the pleura; 3 showed nearly diffuse scarring with early honeycomb change
  • In 12 of the 15 asbestosis cases, the scarred zones had a homogeneous, amphophilic or bluish appearance on standard stains
  • None of the 70 non-asbestosis cases contained asbestos bodies or bluish interstitial matrix
  • Elastic staining showed dense (3+) elastic tissue with marked accentuation around bronchi and bronchioles in 12 asbestosis cases. In the remaining 3 (those with early honeycomb change), elastic tissue was more diffuse and also scored 3+.
  • Elastic tissue was found in 47 non-asbestosis cases: 17 organizing pneumonia, 15 usual interstitial pneumonia/idiopathic pulmonary fibrosis, 4 organizing diffuse alveolar damage, 5 nonspecific interstitial pneumonia, 2 sarcoidosis, 1 desquamative interstitial pneumonia, and 3 amiodarone-related. In these cases it was diffuse or mainly around blood vessels, with no accentuation around airways, and it ranged from 1+ to 3+.
  • Immunostaining for elastin matched the elastic-stain findings in all cases. Collagen was deposited together with elastin wherever elastic tissue was seen.
• The authors' conclusion: The authors concluded that the results supported their hypothesis that asbestosis produces a fibroelastotic response, located preferentially around bronchi and bronchioles. In their view, such a pattern should prompt a search for asbestos bodies and makes a non-asbestos diagnosis less likely.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Interstitial, Interstitial Lung Disease, Autopsy, Pneumonitis, Idiopathic, Pulmonary Fibrosis, Eosinophilic, Asbestos Bodies.

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