Fig. 1

Histopathologic findings of TBLC specimens. a PAP pattern. HE stained tissue demonstrated alveolar filling with eosinophilic material which was positive in periodic acid stain (PAS). (magnification × 100). b Welder’s pneumoconiosis pattern.HE stained tissue demonstrated hyperplasia of alveolar epithelial cells and welding dust deposition. TBLC transbronchial lung cryobiopsy, PAP pulmonary alveolar proteinosis, HE hematoxylin and eosin (magnification × 100)