Malignant mesothelioma in a patient with anthophyllite asbestos fibres in the lungs

Our plain-English summary of Malignant mesothelioma in a patient with anthophyllite asbestos fibres in the lungs, by J.I. Phillips, J. Murray (The Annals of Occupational Hygiene, 2010).

The study

• Authors: J.I. Phillips, J. Murray
• Journal: The Annals of Occupational Hygiene
• Published: 2010;54(4):412-6
• Type of article: Case report
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The amphibole asbestos, anthophyllite, is associated with asbestos-related disease in humans, along with mesothelioma in animal models. In humans, however, there are only three cases of histologically proven malignant mesothelioma of the pleura associated with anthophyllite that have been documented in the English-language literature. A fourth case is presented in a man who lived in South Africa and had anthophyllite in his lung. Anthophyllite was never commercially mined in South Africa. Using scanning electron microscopy, his lung fibre burden was calculated to be 358,000 fibres and 31,000 asbestos bodies per gram of dry weight of lung tissue. The mean aspect ratio of the anthophyllite fibres in the lung was 41.2 (SD = 28.8). No other types of asbestos were detected in the lung. His exposure was almost certainly occupational. He worked in the plastic manufacturing industry and was exposed to talc and asbestos blankets that were used to insulate machinery.

In plain English

This case report described one man in South Africa who died of malignant pleural mesothelioma and had anthophyllite asbestos fibres in his lungs. Born in Hungary in 1931, he worked in South African plastics factories from 1958 to 1972; from 1961 to 1965 he mixed chemicals for plastic manufacture and covered imported machines with asbestos blankets. The diagnosis was confirmed at post-mortem examination. Scanning electron microscopy of lung tissue, counting only fibres longer than 5 micrometres, found 358 000 asbestos fibres and 31 000 asbestos bodies per gram of dry lung tissue, which the authors considered indicative of significant or occupational exposure. All the asbestos fibres were identified as anthophyllite; no other asbestos types were detected. The authors did not have a technique that would have distinguished anthophyllite from talc, and had no details about the blankets. The authors concluded that the most likely exposure was occupational, either from talc used in the plastics industry or from the asbestos blankets. As a single case, it does not show how often this occurs.

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: Case report (one patient), with post-mortem tissue examination and lung fibre burden analysis by scanning electron microscopy with energy dispersive X-ray spectroscopy
• Who was studied: One man, born in 1931 in Hungary, who arrived in South Africa in 1957. He was a chain smoker who later stopped and had been treated for pulmonary tuberculosis and asthma. He presented with chest pain in 2002 and died in 2005 at age 73 of malignant pleural mesothelioma.
• Exposure: Work in South African plastics manufacturing factories from 1958 to 1972, including (1961 to 1965) mixing chemicals for plastic manufacture and covering imported machines with asbestos blankets. The authors identified talc used in the plastics industry, which may be contaminated with anthophyllite, and the asbestos blankets as possible sources. Fibres found in the lung were anthophyllite. Anthophyllite was never commercially mined in South Africa.
• Main results:
  • Lung fibre burden in uninvolved lung tissue (counting only fibres longer than 5 micrometres): 358 000 asbestos fibres and 31 000 asbestos bodies per gram of dry weight of lung tissue. The authors stated this indicates significant or occupational exposure by their laboratory's reference values.
  • Energy dispersive spectroscopy showed all asbestos fibres counted to be anthophyllite; no other asbestos types were detected in the lung.
  • The anthophyllite fibres had a mean length of 36.4 micrometres, mean diameter of 0.94 micrometres and mean aspect ratio of 41.2 (SD 28.8). The authors stated these fibres are asbestiform and not cleavage fragments.
  • The tumour cells stained positive for calretinin, a marker for mesothelial cells, and negative for carcinoembryonic antigen, a marker for adenocarcinoma. Transmission electron microscopy showed tumour cells with long, branching microvilli.
  • The authors noted the fibre burden was low compared with South African chrysotile asbestos workers.
• The authors' conclusion: The authors concluded that cases of pleural mesothelioma attributable to anthophyllite are rare. In this case, they concluded the most likely exposure was occupational, from talc used in the plastics industry or from asbestos blankets used to insulate imported machines.
• Limitations the authors state:
  • The transmission electron microscopy technique of selected area diffraction, which would determine crystalline nature and discriminate between anthophyllite and talc, was not available to the authors.
  • The authors had no details about the asbestos blankets.
  • The preservation of the tumour tissue examined by transmission electron microscopy was poor.
  • The authors cautioned that comparing lung fibre burden data between different laboratories is unwise.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Anthophyllite, Mesothelioma, Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Anthophyllite, Amphibole Asbestos, Mesothelioma, Pleura, Scanning Electron Microscopy (SEM), Asbestos Bodies, Aspect Ratio (Length-to-diameter ratio).

Related studies

• Rarity of mineral fibre pleurisy among persons exposed to Finnish anthophyllite and with low risk of mesothelioma — G. Hillerdal, A. Zitting, et al. (1984)
• Incidence of cancer among anthophyllite asbestos miners in Finland — L.O. Meurman, E. Pukkala, et al. (1994)
• Four cases of mesothelioma among Finnish anthophyllite miners — A. Karjalainen, L.O. Meurman, et al. (1994)
• Rat model demonstrates a high risk of tremolite but a low risk of anthophyllite for mesothelial carcinogenesis — D. Aierken, Y. Okazaki, et al. (2014)
• Anthophyllite asbestos: state of the science review — S.H. Gaffney, M. Grespin, et al. (2017)
• Re: Malignant mesothelioma from neighborhood exposure to anthophyllite asbestos — M. Kottek, D. Kilpatrick (2002)

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