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Epidemiologic aspects of childhood mesothelioma.

Our calculation provides the first population-based incidence rate of childhood mesothelioma in the United States. Based on these data and on our pathology review, we conclude that mesothelioma occurs rarely in children and that this diagnosis is difficult to establish. A more systematic approach to identifying mesothelioma cases in children, as well as adults, will be facilitated by increasing state surveillance of cancer incidence and by the proposed addition of a unique code for mesothelioma in the Tenth Revision of the ICD. There is a critical need for histopathological verification of mesothelioma cases. The increased use of a uniform, reproducible histopathologic classification and mesothelioma panels should address this problem. A thorough microscopic study of individual cases needs to be supplemented by a careful assessment of the clinical findings and environmental factors. The available data thus far do not support an association between childhood mesothelioma and asbestos exposure. However, the ubiquitous nature of asbestos exposures, the known association of asbestos with adult mesothelioma, the unreliability of the diagnosis, and the lack of adequate data regarding asbestos exposures, all indicate that asbestos involvement cannot be categorically ruled out, especially in older children with the potential for a longer duration of exposure and a plausible induction period. Mesothelioma in children, as well as in adults, is likely to have a multifactorial etiology. Radiation, prenatal medications, and genetic factors are all possible etiologic agents in childhood mesothelioma. In addition, other, as of yet unspecified environmental factors may play a role in this disease. When cases are diagnosed, the physician should inquire about the history of exposure to asbestos or other hazardous materials in the patient's environment, prior radiation exposure, medication exposure pre- and postnatally, prior cancer diagnoses, and a family history of cancer. An interdisciplinary approach, combining the diagnostic skills of the pathologist and the analytic skills of the epidemiologist, will be of value and of special relevance in the study of mesotheliomas.