a) Iron stain showing welder’s lung and various lung segments consistent with welder’s lung changes: fibrosis with carbon and iron pigment. b) Lung tissue with scarring, abundant histiocytes and multinucleated giant cells containing pigment both iron and ca... a) Iron stain showing welder’s lung and various lung segments consistent with welder’s lung changes: fibrosis with carbon and iron pigment. b) Lung tissue with scarring, abundant histiocytes and multinucleated giant cells containing pigment both iron and carbon. The alveoli contain numerous macrophages and chronic inflammatory cells. At higher magnification, there is dystrophic calcification and ossification. c and d) Lymph nodes with a lot of pigment deposition but no evidence of malignancy. Sofia G. Korsavva, and Sudipta Roy Breathe 2017;13:e114-e120 ©2017 by European Respiratory Society