Figure 3. (A-D) The pathological results of the removed pill-like material and biopsy tissue around the pill-like material in the right bronchus intermedius revealed aspiration of ferrous sulfate. (A) Removed pill-like material. (B) Bronchus intermedius (A and B, H&E stain, ×100; C, H&E stain, ×400; D, iron stain, ×400).