In all patients, lung tissue was available for asbestos digestion analysis. This was performed using a slight modification of the Smith and Naylor technique. In cases 1, 2, and 4, lung tissue showing the pathologic changes described herein was removed from the paraffin block. In our experience, lung tissue processed from paraffin for asbestos quantitation typically shows a 10 to 25 percent decrease in asbestos body content compared with nonprocessed, paraffin-embedded tissue. The asbestos fiber analysis in case 6 was performed in the laboratory of Dr. Ronald F. Dodson, according to his procedure.
Sections of lung tissue were routinely stained with hematoxylin-eosin, Movat pentachrome, Ziehl-Neelsen, Gomori methenamine silver, and Brown-and-Brenn tissue Cram stain. Portions of lung tissue from cases 1, 2, 5, 6, and 7 were cultured for routine bacteria, mycobacteria, and fungi. The histologic sections were carefully examined for the presence of intranuclear and cytoplasmic viral inclusions.

Results
As shown in Table 1, the patients symptoms were nonspecific, the most frequent being dyspnea on exertion; case 1 was asymptomatic. In cases 1, 2, 4, 5, and 6, the chest radiographs showed localized nodules that were close to the pleural surface, but not in contact with it. These were usually diagnosed radiographically as being suspicious for a neoplasm and in this group of patients were thought to represent primary lung neoplasms. A thoracotomy was performed on each patient to remove a suspected lung neoplasm.