Abnormal pleura morphology Pleural plaque 2021-01-09T14:32:56Z Pleural plaques are indicative of asbestos exposure. Grossly, the pleural plaque is characterized by hyalinized discrete elevated gray-white or pearly areas involving the parietal pleura. Despite varying sizes and shapes, the pattern of the plaques is repetitive. There is a flat or slightly uneven surface, with steep edges rising abruptly from the surrounding normal pleura, and here and there rounded mounds, with somewhat overhanging edges. The thick pleural plaques are typical in appearance, and the classic comparison is to frosting or sugar icing (Zuckerguss), as is seen on serous membranes. Deposits of hyalinized collagen fibers in the parietal pleura (preferentially pleura adjacent to ribs, particularly the sixth through ninth ribs).