This patient previously worked as a stone mason for a long period of time. The imaging features are those of progressive massive fibrosis and, in this clinical setting, most likely due to silicosis. 

He was then further submitted to a single lung transplant and the resected right native lung was assessed histologically: 

Macroscopy: Right native lung weighing 696 g measuring 190 x 181 x 87 mm. Pleura appears grey/tan with roughened texture and patchy areas of hemorrhage. Bronchovascular resection margins are clear. Hilar lymph nodes appear carbon pigmented. On sectioning within all lobes, there are central areas of pale tan fibrosis intermixed with black pigmentation. There is some sparing of the parenchyma at the base of the lower lobe and periphery of the upper and middle lobes. No solid lesions are identified. No thrombi are identified.

Microscopy: Sections from all lobes show marked distortion of the alveolar architecture by interstitial fibrosis including prominent coalescing nodules of hyalinised tissue containing polarisable flecks of silica. There is relative sparing of the more peripheral and subpleural zones, as well as the lower lobe,  where there is a preservation of the alveolar architecture with only mild interstitial expansion with a mononuclear inflammatory cell infiltrate. No well-formed granulomas are seen. Thromboemboli are not identified. No hyaline membranes are present. No viral inclusions are seen.

Hilar lymph nodes also show parenchymal nodular silicosis. There is no evidence of malignancy.

Diagnostic Opinion: Right native lung, explant: Nodal and parenchymal silicosis with severe interstitial fibrosis.