All available pulmonary histologic findings were reviewed by three of us (R.F.S., R.H.H., and G.M.H.). A mean of eight slides was examined for each patient. Pulmonary sections were graded without knowledge of the patients group for peribronchiolar fibrosis, other types of fibrosis, emphysema, and pleural change. The degree of peribronchiolar fibrosis (Fig 2A) was scored from 0 to 12 based on the scheme for grading asbestosis established by the Pneumoconiosis Committee of the College of American Pathologists and the National Institute of Occupational Safety and Health in 1982. The score is the product of two grades, one for severity (scored 0 to 4) and the other for extent of involvement (scored 1 to 3).
Other types of fibrosis (alveolar, interstitial, and large scar) were each graded on a scale of relative severity ranging from 0 to 4 (least to greatest). Alveolar fibrosis (Fig 2B) was defined as fibrosis primarily involving the alveolar spaces (organizing pneumonia). Interstitial fibrosis (Fig 3A) was defined as fibrosis sparing the air spaces and predominantly involving the alveolar walls and interlobular septa. Large scar fibrosis (Fig 3B) was defined as fibrous bands obliterating the underlying pulmonary architecture. The relative degrees of pleural thickening and of centrilobular and scar-related emphysema were graded on a scale from 0 to 3 (least to greatest). The presence or absence of asbestos bodies was noted. The paired f-test or the x2 test was used in all statistical analyses. fully
The studied group included 82 men and 11 women, 60 whites and 33 blacks, and their ages ranged from 25 to 91 years of age (mean, 65 years) (Table 1). Fifty-six of these patients had a history of cigarette smoking documented in their postmortem records. Eighteen had primary pulmonary neoplasms, and 12 had pulmonary metastases from extrapulmonary malignancies. Seventeen had received radiation therapy, and 16 had had chemotherapy. Of the control patients, 42 were smokers. Nine had primary pulmonary neoplasms, and 12 had metastases to the lung. Eighteen had undergone radiation therapy, and 20 had received chemotherapy.
Figure 2 A (top). Peribronchiolar fibrosis with associated anthra-cosis in control patient. Peribronchiolar fibrosis was neither universally nor exclusively present in patients with pleural plaques. B (bottom). Alveolar fibrosis, characterized by fibrosis involving alveolar spaces (organizing pneumonia), was more common in patients with pleural plaques (hematoxylin-eosin, original magnification x 75).
Figure 3 A (top). Interstitial fibrosis was seen in both cases with pleural plaques and control patients. In this case, fibrosis appeared to be secondary to deposition of iron in an arc welder. B (bottom). In contrast to interstitial fibrosis, large-scar fibrosis obliterates underlying pulmonary architecture (hematoxylin-eosin, original magnification x75).
Table 1—Demographic Features
|Data||Patients with Pleural Plaques||Controls|
|No. of subjects||93||93|
|Mean age, yr||65||65|
|Sex ratio (male/female)||82/11||82/11|
|Primary pulmonary neoplasms||18||9|