[Autopsies of five coal workers with pleural plaque]

Data from autopsies for 200 coal workers were analyzed to study the significance of pleural plaque in diagnosis for pneumoconiosis. Parietal Pleural plaques were found in them. Macroscopically, pleural plaques could be divided into two types, one smooth and the other nodular. Under microscope, typical pleural plaques were composed of a basket-woven, coarse collagen fiber arrayed in parallel, and nodular plaques were collagen fiber arrayed in a folding pattern. Ferruginous bodies could be seen among collagen fiber in the histological sections of pleural plaques. It suggests that corresponding amendement to the national diagnostic criteria for pneumoconiosis is necessary.