Pathology of malignant mesothelioma

Our plain-English summary of Pathology of malignant mesothelioma, by R.L. Attanoos, A.R. Gibbs (Histopathology, 1997).

The study

• Authors: R.L. Attanoos, A.R. Gibbs
• Journal: Histopathology
• Published: 1997;30(5):403-18
• Type of article: Review
• Cited by: 204 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The diagnosis of malignant mesothelioma can pose several problems to the surgical pathologist. First, the morphological appearances of the tumour are known to be diverse with mimicry of a range of both reactive and neoplastic conditions. Second, due to the relative inaccessibility of the serosa, biopsy material is often scanty and fragmentary, producing a plethora of interpretive ambiguities. Third, adjunct techniques such as mucin histochemistry and immunohistochemistry, whilst useful in excluding malignant mesothelioma have little role in confirming the diagnosis. The accurate diagnosis of diffuse malignant mesothelioma is important for two reasons: (1) In relation to prognosis as it has an almost invariable fatal outcome, which contrasts with the other mesothelial neoplasms such as the benign adenomatoid tumour and the borderline malignant tumours, namely the well-differentiated papillary mesothelioma and multicystic mesothelioma; (2) In relation to occupational-related compensation claims following asbestos exposure. This review summarizes the aetiology of asbestos-induced neoplasia, possible mechanisms of tumour development and highlights potential diagnostic pitfalls.

In plain English

This article was an invited review of the pathology of malignant mesothelioma by two UK pathologists. It did not report a new study of patients. The authors summarized published work on causes, possible mechanisms and diagnosis. They stated that in the UK 80% to 90% of mesotheliomas appear to be related to prior asbestos exposure. They wrote that studies showed a clear-cut difference in potency between asbestos fibre types, with crocidolite the most potent, and that chrysotile alone rarely, if ever, causes mesothelioma. Citing an earlier review of 1690 cases, they reported that 99% had a latent period, counted from first asbestos exposure to death, of over 15 years, with a median of 32 years. They described other suggested causes: erionite in Cappadocian Turkey (which they described as much more potent than crocidolite), radiation and Simian virus-40. Most of the review explained how pathologists distinguish mesothelioma from tumours and conditions that resemble it. The authors stated that immunohistochemistry mainly helps confirm a tumour is not mesothelioma. They concluded that accurate diagnosis matters for prognosis and for asbestos compensation claims.

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: Narrative review (invited review) of published literature on the causes, mechanisms and pathological diagnosis of malignant mesothelioma, including the authors' own diagnostic experience
• Who was studied: No new patient group was studied. The review covered published research and case series on malignant mesothelioma of the pleura, peritoneum, pericardium and tunica vaginalis testis, and on related mesothelial lesions.
• Exposure: Asbestos, in the serpentine form chrysotile and the amphiboles crocidolite, amosite, anthophyllite and tremolite. The review also discussed non-asbestos factors: erionite, organic fibres, man-made mineral fibres, radiation and thorotrast, Simian virus-40, chronic inflammation, heavy metals and familial cases.
• Main results:
  • The authors stated that in the UK 80% to 90% of mesotheliomas appear to be related to prior asbestos exposure.
  • According to the review, epidemiological studies comparing asbestos fibre types showed a clear-cut difference in mesothelioma potency, with crocidolite ranked highest among them. The authors stated that chrysotile alone rarely, if ever, causes mesothelioma.
  • The review stated that erionite, a non-asbestos mineral fibre, has physical properties similar to crocidolite but much greater mesothelioma potency in both animal and human studies.
  • The review defined latency as the time from first exposure to asbestos to death from the disease.
  • Citing an earlier review of 1690 mesothelioma cases, the authors reported that 99% had a latent period of more than 15 years and 96% at least 20 years. The median latent period was 32 years.
  • The review stated that chrysotile fibres are cleared from the lung much more efficiently than amphibole fibres. As a result, lung fibre counts reflect past amphibole exposure but not past chrysotile exposure.
  • The review stated that approximately 50% of pleural and 75% of peritoneal mesotheliomas are of epithelial pattern and 30% are biphasic. The remainder (15% to 20%) are pure sarcomatous.
  • Carbone et al. reported SV-40-like sequences in approximately 60% of human mesotheliomas. The authors reported that their own laboratory had obtained similar results in a limited group of human mesotheliomas.
  • The review stated that no excess risk of mesothelioma had been described, to date, in people exposed to man-made mineral fibres.
  • For the borderline or benign mesothelial lesions, the authors stated there is no clear association between well-differentiated papillary mesothelioma and asbestos. They also stated there is no known association between multicystic mesothelioma and asbestos exposure.
  • The authors stated that immunohistochemistry is the most useful ancillary method, but that its diagnostic use lies mainly in confirming a tumour as not mesothelioma.
  • For suspected cases at post mortem, the authors described electron microscopic mineral analysis of digested lung tissue as a step to consider when no asbestos bodies are seen by light microscopy.
• The authors' conclusion: The authors concluded that accurate diagnosis of mesothelioma is essential both for prognosis and for occupational compensation claims after asbestos exposure. They added that in most cases additional tests are needed to confirm the diagnosis made by microscopy.
• Limitations the authors state:
  • The authors stated that the accuracy of UK mesothelioma statistics from the Health and Safety Executive Mesothelioma Register and death certificates is questionable, particularly for peritoneal mesothelioma.
  • The authors stated that how asbestos causes these tumours is poorly understood.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Peritoneal mesothelioma.

Medical terms in this study, explained in our Lexicon: Pathology, Malignant Mesothelioma, Biopsy, Immunohistochemistry, Prognosis, Neoplasm, Adenomatoid Tumor, Well-Differentiated Papillary Mesothelioma.

Related studies

• Surgical pathology of primary cardiac and pericardial tumors — C. Basso, M. Valente, et al. (1997)
• Analysis of latency time and its determinants in asbestos related malignant mesothelioma cases of the Italian register — A. Marinaccio, A. Binazzi, et al. (2007)
• Selected topics in peritoneal pathology — P.M. Baker, P.B. Clement, et al. (2014)
• The pathology associated with therapeutic procedures in malignant mesothelioma — R.L. Attanoos, A.R. Gibbs (2004)
• The pathology of mesotheliomata and an analysis of their association with asbestos exposure — D.O. Hourihane (1964)
• CT-guided core-needle biopsy in omental pathology — F. Pombo, E. Rodriguez, et al. (1997)

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