The role of smoking and exposure to asbestos and man-made vitreous fibers in a questionable case of mesothelioma.

A remaining uncertainty in the U.S. cohort study of man-made vitreous fiber (MMVF) workers is whether asbestos exposure contributed to 10 questionable cases of mesothelioma. We report further details on one case from our previous mesothelioma investigation, including results of a recent lung tissue analysis. Case is a 68 year-old white male employed 1951-54 in a rock/slag wool plant where asbestos-containing products were manufactured. Cause of death was recorded as "mesothelioma, malignant, right pleural cavity" (ICD9: 163.9). Analysis for presence of asbestos bodies identified 18,300 asbestos bodies per gram of wet lung tissue (AB/gm), which greatly exceeds the normal range of 0-20 AB/gm. No MMVFs were identified in this sample. We conclude that this patient's tumor was not a mesothelioma, but a carcinoma possibly arising in the lung or mediastinum, and that this case supports the view that the few suspected mesotheliomas found in the U.S. cohort may have been caused by asbestos exposure.