Fig. 3.

Microscopy of transbronchial biopsies taken blindly are intended to represent alveolar lung parenchyma. Sometimes these samples are dominated by bronchial mucosa and cartilage if a branch point is directly sampled (a minor carina). This sample shows airway mucosa, lamina propria, and musculature samples with fragments of partially ossified (dark blue) cartilage. Scant alveolar parenchyma is present in the lower left of this image. Hematoxylin and eosin stain, original magnification, ×100.