Bronchoscopic visualization of the alveoli.

We report a rare case in which we were able to visualize the lung alveoli through the bronchial wall by a bronchoscope in a patient with marked bronchiectasis and performed lung biopsy safely under direct vision. An 80-year-old woman presented with complaints of a severe persistent cough for the past 6 months. A chest computed tomography scan revealed diffuse interstitial pneumonia with marked bronchiectasis. Bronchoscopy also revealed marked bronchiectasis. After inserting the bronchoscope into the 10th-generation bronchus, we observed a honeycomb pattern through the bronchial wall, which represented the alveoli. We perforated the bronchial wall by using biopsy forceps and performed lung biopsy under direct vision. The pathologic diagnosis revealed interstitial pneumonia with epithelioid granuloma and cholesterin-like substance, which were indicative of hypersensitivity pneumonia. The routine performance of true "trans"-bronchial lung biopsy will be possible if a thin bronchoscope with high-quality imaging is developed in the future.