Evaluation of the pleural malignant mesothelioma patients with the relation of asbestos exposure

There has been a recent increase in the number of patients with malignant mesothelioma in parts of Japan where Naval shipyards were located during World War II. This can be attributed to asbestos exposure during work in the shipyard. We have studied eight patients who were seen between 1984 and 1986 in Kure Kyosai Hospital. All had a history of asbestos exposure, seven in a Naval shipyard. In these seven cases, the latent period between exposure and the appearance of mesothelioma was 43-49 years. Quantification of asbestos bodies in the lung indicated a high concentration in all patients, giving further weight to the concept that asbestos is an etiologic factor in the genesis of mesothelioma. The major types of asbestos fibers were crocidolite and amosite. The study of structural features of these two types may provide a clue to the pathogenesis of the disease.