Bronchiolar adenoma with unusual presentation: Two case reports

Figure 4 Pathological features of case 2. A: At low magnification (100 ×, frozen section), the boundary of the tumor was relatively clear; there were air cavities and arterioles were visible; B: At high magnification (200 ×, frozen section), the tumor cells were found to be mainly arranged in a monolayer with locally visible cilia (arrows); some nuclei appeared enlarged and atypical (star); C: At low magnification (100 ×), most cells appeared with moderate density (star), focal hyperplasia, and stroma within the focal lymphocytic infiltration; D and E: Observations at medium to high magnification (200 × and 400 ×, respectively) revealed that the tumor cells were arranged as an acinar structure and accessory wall structure; most cells were not atypia in shape, and cilia (arrow) were seen. Some nuclei were enlarged and atypical (circle).