Figure 4c. CT scans and autopsy findings in an 86-year-old man with silicosis (former metal ore miner). (a, b) Transverse CT scans obtained with 10-mm collimation. (a) Lung window scan shows a rounded opacity (PMF) in the right lower lobe. Lung volume is reduced, and the major fissure is displaced (arrows). CT features were those of rounded atelectasis. Note multiple small nodules of silicosis in both lower lobes. (b) Mediastinal window scan at the same level as in a shows a thickened band (arrow) that connects PMF with the thickened pleura. There is a small amount of ipsilateral pleural effusion and multiple calcifications in the PMF. (c) Gross lung specimen from a coronal section shows diffuse pleural thickening in the right lung base and invagination (arrow) into the mass. (d) Photomicrograph shows coalescence of calcified silicotic nodules forming the mass. Intervening lung tissue is black pigmented and shows various degrees of interstitial fibrosis and atelectasis. The pathologic features were compatible with PMF. Invagination of thickened pleura (arrows) into the mass is apparent. (Elastic-Goldner stain, original size.)