Parietal pleural plaques, asbestos bodies, and neoplasia. A clinical, pathologic, and roentgenographic correlation of 25 consecutive cases.

An investigation was made to correlate autopsy and roentgenographic findings of pleural plaques with occupational exposure to asbestos and occurrence of respiratory tract tumors. Of the 434 autopsies performed over a 2 1/2 year period, 25 (5.8 percent) had pleural plaques but no gross evidence of parenchymal fibrosis. Review of the posterior-anterior chest roentgenograms using the International Labor Office criteria for classification of pneumoconiosis (1980) revealed that only seven of the 25 cases had detectable pleural thickening or calcification, which demonstrates the poor sensitivity of standard x-ray films. There was no detectable difference in frequency of known or presumed exposure to asbestos between the pleural plaque cases and controls as determined by occupational information obtained from chart review. Asbestos bodies were identified in lung tissue digests from all 25 cases with pleural plaques, and exceeded the normal range for our laboratory in 14 cases (56 percent). Of the 25 cases with pleural plaques, four also had bronchogenic and three had laryngeal carcinoma. The prevalence of bronchogenic carcinoma in patients with plaques was not different from those without plaques (p greater than 0.50). However, the association between plaques and laryngeal carcinoma was highly significant (p = 0.004).