The pathology of parietal pleural plaques

Our plain-English summary of The pathology of parietal pleural plaques, by G.H. Roberts (Journal of Clinical Pathology, 1971).

The study

• Author: G.H. Roberts
• Journal: Journal of Clinical Pathology
• Published: 1971;24(4):348-53
• Cited by: 52 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 002701).

Abstract

The incidence, morbid anatomy, histology, and relationship of hyaline pleural plaques to exposure to asbestos has been studied. Plaques were found in 12.3% of 334 hospital necropsies (in an urban population in Glasgow, 41 cases). In 85.3% (35 cases) asbestos bodies were found in the lungs. There is evidence of a dose-response relationship between the number of asbestos bodies found in the lungs and the presence of pleural plaques. The selective distribution of plaques within the pleural cavities suggests that mechanical factors play a part in their localization. Histological examination contributed little to understanding the mechanism of plaque formation; that asbestos bodies have been detected in only a few cases suggest that their presence in the parietal pleura is not essential to plaque formation. The suggested mechanisms of plaque formation are discussed.

In plain English

This 1971 autopsy study came from a Glasgow general hospital serving a heavily industrialized area near the Clyde shipyards. The author examined the chest linings of 334 hospital necropsies for hyaline plaques on the parietal pleura and counted asbestos bodies in smears from the lower lungs. Plaques were found in 41 of 334 cases (12.3%), and only one was in a woman. Asbestos bodies were found in 35 of the 41 plaque cases (85.3%). The author reported a statistically significant difference in plaque frequency between cases with and without asbestos bodies. Plaques were found in 9 of 57 cases (15.8%) with fewer than five bodies, 32.6% of 52 cases with five to 50 bodies, and all 8 cases with more than 100 bodies. Plaques lay mostly on the back wall of the lower chest. Under the microscope, no asbestos bodies were seen in plaque sections, and an extraction technique found scanty bodies in two of 28 cases. The author concluded the results supported a causal relationship between plaques and asbestos exposure, while suggesting other, unidentified causes may exist. Detailed occupational histories were not available.

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: Autopsy (necropsy) series examining the pleural cavities for plaques and counting asbestos bodies in lung smears, with microscopic study of a subset of plaques
• Who was studied: 334 hospital necropsies at the pathology department of a general hospital (Southern General Hospital) serving about 250,000 people in heavily industrialized south-west Glasgow, near the Clyde shipbuilding industry; part of an earlier series of 400 consecutive necropsies; dates of the necropsies not stated
• Exposure: Asbestos bodies counted in smears from the basal segments of both lower lobes (300 low-power fields per slide; table reports bodies per 600 fields); fiber types not identified; last known occupation noted from clinical notes where available
• Main results:
  • Hyaline pleural plaques were found in 41 of 334 necropsies (12.3%)
  • Only one of the 41 cases with plaques was female
  • Among the 41 cases with plaques, asbestos bodies were found in the lung smears of 35 (85.3%)
  • The author reported a statistically significant difference in the incidence of plaques between cases with and without asbestos bodies in the smears (chi-square 22.0, p less than 0.001)
  • Plaques were found in 9 of 57 cases (15.8%) with fewer than five bodies counted, and in 32.6% (17 cases) of 52 cases with five to 50 bodies
  • Plaques were present in all eight cases with more than 100 asbestos bodies counted
  • Occupations were recorded for 33 of the 40 males with plaques, and in 13 of them the shipyards were specifically mentioned as the place of work
  • Plaques were most common on the posterior wall of the lower half of the pleural spaces
  • No plaques were found at the apices of the pleural cavities, in the costophrenic angles, or on the anterior wall near the costochondral junction
  • In the 28 cases examined under the microscope, no inflammatory cells were present in the plaques
  • In the 28 cases examined under the microscope, no asbestos bodies were seen in plaque sections; scanty bodies were found in two cases by the extraction technique
  • The author suggested that, because asbestos fibres or bodies were detected in so few parietal plaques, their presence is not necessary to produce plaques
  • The author suggested that although asbestos exposure is the commonest cause of pleural plaques, unidentified causes may still exist
• The authors' conclusion: The author concluded that the results support the causal relationship between hyaline parietal pleural plaques and exposure to asbestos
• Limitations the authors state:
  • No detailed occupational history was available for any case
  • The author stated that fuller occupational details would have shown a higher proportion of shipyard workers

Topics

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

Medical terms in this study, explained in our Lexicon: Pathology, Pleural Plaques, Histology, Asbestos Bodies, Dose-response relationship, Parietal Pleura.

Related studies

• 'Black Spots' and hyaline pleural plaques on the parietal pleura of 150 urban necropsy cases — K. Mitchev, P. Dumortier, et al. (2002)
• Surgical implications of parietal pleural plaques — P.C. Pairolero, P.H. Bernatz, et al. (1973)
• Black spots concentrate oncogenic asbestos fibers in the parietal pleura. Thoracoscopic and mineralogic study — C. Boutin, P. Dumortier, et al. (1996)
• Chrysotile and tremolite asbestos fibres in the lungs and parietal pleura of Corsican goats — P. Dumortier, F. Rey, et al. (2002)
• Asbestos, carbon nanotubes and the pleural mesothelium: a review of the hypothesis regarding the role of long fibre retention in the parietal pleura, inflammation and mesothelioma — K. Donaldson, F.A. Murphy, et al. (2010)
• Length-dependent retention of carbon nanotubes in the pleural space of mice initiates sustained inflammation and progressive fibrosis on the parietal pleura — F.A. Murphy, C.A. Poland, et al. (2011)

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