[A case of arc welder's lung with ground-glass opacities and progressive massive fibrosis].

A 62-year-old man who had worked as a welder for 35 years was admitted with abnormal chest radiograph shadows. Chest CT scan showed ground-glass opacities (GGO) and nodular shadows (progressive massive fibrosis: PMF) with spiculation in both lung fields. Transbronchial lung biopsy (TBLB) findings of a nodule (left segment 8) revealed many iron particles in the alveoli and positive staining for Fe (Berlin blue stain). Moreover, bronchoalveolar lavage (BAL) fluid of a GGO (left segment 4) revealed many iron particles and positive staining for Fe (Berlin blue stain) in macrophages. Serum ferritin was extremely high (6.352 ng/ml) and ferritin in the BAL fluid was 210 ng/ml. Taking the clinical course and pathological findings together, pneumoconiosis (arc welder's lung) was diagnosed. The most common chest CT pattern in arc welder's lung is ill-defined micronodules diffusely distributed in the lung like hypersensitivity pneumonitis. Arc welder's lung rarely presents as PMF. We report a case of arc welder's lung accompanied with PMF.