Figure 1.

Grading of bronchiolocentric fibrosis. A. No bronchiolocentric fibrosis, score = 0. The peribronchiolar alveolar septa are thin and without significant fibrosis. B. Mild bronchiolocentric fibrosis, score = 1. There is peribronchiolar metaplasia with slight alveolar septal fibrosis. C. Moderate bronchiolocentric fibrosis, score = 2. There is peribronchiolar metaplasia with prominent alveolar septal thickening extending across half of the pulmonary lobule. D. Severe bronchiolocentric fibrosis, score = 3. There is peribronchiolar metaplasia and bronchiolocentric fibrosis with loss of normal alveolar architecture. Scale bars = 500 μm).