Mesothelioma from chrysotile asbestos: update

PURPOSE

There are different mineral classes of asbestos, including serpentines and amphiboles. Chrysotile is the main type of serpentine and by far the most frequently used type of asbestos (about 95% of world production and use). There has been continuing controversy over the capability of chrysotile asbestos to cause pleural and peritoneal mesothelioma. This review is to help clarify the issue by detailing cases and epidemiology studies worldwide where chrysotile is the exclusive or overwhelming fiber exposure.

METHODS

A worldwide literature review was conducted of asbestos and associated mesothelioma including case series, case-control and cohort epidemiology studies searching for well documented chrysotile asbestos associated mesothelioma cases.

RESULTS

Chrysotile asbestos exposures have occurred in many countries around the world from mining, manufacturing and community exposures. There have been many documented cases of mesothelioma from those exposures.

CONCLUSIONS

Chrysotile asbestos, along with all other types of asbestos, has caused mesothelioma and a world-wide ban of all asbestos is warranted to stop an epidemic of mesothelioma.

Pleural mesothelioma and household asbestos exposure

This article discusses the development of asbestos-induced malignant mesotheliomas after non-occupational environmental exposure to asbestos through contact with occupationally exposed household members. In our policlinic, we have seen six fatal pleural mesothelioma cases (five wives and one son of asbestos-industry workers) with no history of occupational asbestos exposure. In five women, a causal relation was established between the fatal disease and inhalation of asbestos fibers while cleaning the contaminated work-clothes and shoes of their husbands at home. The son had also been exposed to asbestos throughout his childhood during daily visits with his father at the workplace.

Asbestos-associated pleural mesothelioma in school teachers: a discussion of four cases

The causal relationship between malignant mesothelioma and exposure to asbestos is well established. In part as a result of that association, much public attention has focused on asbestos abatement in buildings, such as public schools, in which that asbestos was used as a construction material. The present communication is a report of four cases of malignant mesothelioma in school teachers whose only apparent exposure to asbestos was in the schools in which they taught. The concerns raised by this report are also discussed.

Absence of evidence for a significant background incidence of diffuse malignant mesothelioma apart from asbestos exposure

The incidence of diffuse malignant mesothelioma is rising. Physicians can diagnose a disease only when they know that it exists, so one explanation for the rise in incidence is more widespread appreciation of the clinical and pathological features of the disease. Modern pathology has ascribed specific requirements for the diagnosis of diffuse malignant mesothelioma. A priori one cannot assume that these requirements have increased the likelihood of the diagnosis because the requirements also can serve to exclude the diagnosis depending on the findings. Most cases of diffuse malignant mesothelioma are suspected by macroscopic and routine microscopic techniques that have been available since the last part of the nineteenth century. Although single reported instances of some pulmonary diseases have survived from the nineteenth century, pathologists did not identify enough cases to convincingly establish the existence of diffuse malignant mesothelioma of the pleura as an entity until the 1930s or 1940s. One must conclude that the background level of diffuse malignant mesothelioma in Europe and in the United States prior to 1930 was extremely low. No case was detected at the Massachusetts General Hospital until 1946.