Black spots of the parietal pleura: morphology and formal pathogenesis

Our plain-English summary of Black spots of the parietal pleura: morphology and formal pathogenesis, by K.M. Müller, I. Schmitz, K. Konstantinidis (Respiration; International Review of Thoracic Diseases, 2002).

The study

• Authors: K.M. Müller, I. Schmitz, K. Konstantinidis
• Journal: Respiration; International Review of Thoracic Diseases
• Published: 2002;69(3):261-7
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Dark incorporations (black spots) have been described in various organs. 'Black spots' seen as flat-to-nodular lesions of the parietal pleura are common findings in former miners. They represent areas of coal dust accumulation. An increased incorporation of asbestos fibres has been described in these areas, causing them to be seen as potential starting points for malignant mesotheliomas.

Objectives: The aim of our examinations was to describe the morphology of black spots in order to understand their formal pathogenesis and discuss their role in the development of malignant mesotheliomas.

Materials: We report the results of the morphological and energy dispersive X-ray analysis of 12 black spots (4 surgical and 8 autopsy specimens) located in the parietal pleura.

Results: Black spots of the pleura develop in close correlation to lymphatic channels and blood vessels. Their formal pathogenesis is characterized by a mild fibrosis and an inflammatory reaction to the incorporated foreign particles. The proliferation of connective tissue may result in the formation of hyaline granulomas. Aluminum, silicone and sometimes fibres are also found in such areas. Mesothelial cells may be irritated.

Conclusion: Although there are hints for an increased proliferation of mesothelial cells in some areas with black spots, our findings do not support the classification of black spots as an obligate early lesion in the development of malignant mesotheliomas.

Copyright 2002 S. Karger AG, Basel

In plain English

This laboratory pathology study examined 'black spots': dark patches of deposited mixed dust in the parietal pleura (the lining of the chest wall), which the authors describe as common in former coal miners. The authors examined 12 black spots (4 surgical and 8 autopsy specimens) using light microscopy, immune staining, electron microscopy and X-ray analysis of the elements present. The black spots lay along lymphatic channels. Most were 0.5 to 1 mm thick, and thicker nodular ones were rare. They showed a usually mild inflammation with T- and B-lymphocytes, and the lining (mesothelial) cells over nodular spots could enlarge and multiply. The deposits were mainly silicon- and aluminum-containing (the article writes 'silicone'), including silicates, quartz and muscovite. In their group of former Ruhr-area miners, the authors did not find asbestos fibres directly in black spots. Some black spots lay near hyaline pleural plaques, but the two lesions shared only one feature. The authors concluded that their findings do not support classing black spots as an obligate early lesion of malignant mesothelioma.

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: Descriptive pathology study (microscopic, immunohistochemical, electron microscopic and energy dispersive X-ray analysis of tissue specimens)
• Who was studied: 12 black spots of the parietal pleura from 12 patients (4 surgical and 8 autopsy specimens), Institute of Pathology, Bochum, Germany; the authors refer to their group as former miners of the Ruhr area
• Exposure: Mixed dust (coal dust) pigment deposits in the parietal pleura. The specimens were examined for elements and for fibres, including asbestos. No individual exposure histories or doses are given.
• Main results:
  • Black spots appeared as flat, punctate or planar dark pigmentations along the lymphatic channels of the parietal pleura.
  • Most black spots were only slightly raised, 0.5 to 1 mm thick; nodular black spots 2.5 to 4 mm thick were rare.
  • Immunohistochemistry confirmed T- and B-lymphocytes within black spots; the inflammatory reaction was usually mild.
  • Mesothelial cells covering nodular black spots could focally lose their flat shape, hypertrophy and proliferate.
  • Element analysis showed a heterogeneous distribution of predominantly silicone- and aluminum-containing deposits (the article's term 'silicone').
  • The authors found silicates, quartz and silicone, as well as aluminum-rich minerals such as muscovite.
  • In their group of former Ruhr-area miners, the authors did not find asbestos fibres, especially amphibole fibres, located directly in black spots.
  • In some specimens black spots occurred together with or close to hyaline pleural plaques. Proliferation of collagen fibres was the only feature the two lesions had in common.
• The authors' conclusion: The authors concluded that their results do not support the hypothesis that mesotheliomas develop preferentially in pre-existing black spots, or that black spots are an obligate early lesion in the development of malignant mesothelioma.
• Limitations the authors state:
  • The authors state that the role of black spots in mesothelioma development can only be settled by continued observation of patients after black spots are first diagnosed at thoracoscopy.

Topics

Medical terms in this study, explained in our Lexicon: Parietal Pleura, Malignant Mesothelioma, Autopsy, Pleura, Fibrosis, Granuloma, Mesothelial Cells.

Related studies

• Black spots concentrate oncogenic asbestos fibers in the parietal pleura. Thoracoscopic and mineralogic study — C. Boutin, P. Dumortier, et al. (1996)
• 'Black Spots' and hyaline pleural plaques on the parietal pleura of 150 urban necropsy cases — K. Mitchev, P. Dumortier, et al. (2002)
• 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)
• Evaluation of the fate and pathological response in the lung and pleura of brake dust alone and in combination with added chrysotile compared to crocidolite asbestos following short-term inhalation exposure — D.M. Bernstein, R.A. Rogers, et al. (2015)
• 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)
• Chrysotile and tremolite asbestos fibres in the lungs and parietal pleura of Corsican goats — P. Dumortier, F. Rey, et al. (2002)

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