Figure 1d. Idiopathic pulmonary fibrosis in a 47-year-old woman. (a) High-resolution CT scan demonstrates ground-glass attenuation in a peripheral distribution. There is interlobular septal thickening, irregularity of the fissures (arrowheads) and bronchiectasis (arrows) consistent with early usual interstitial pneumonia. (b) High-resolution CT scan acquired 22 months later shows progression of usual interstitial pneumonia, manifested as diffuse ground-glass attenuation, interlobular septal thickening (arrows), and a honeycomb pattern (arrowhead). (c) Photomicrograph (original magnification, x12.5; hematoxylin-eosin stain) reveals cystically dilated air spaces that constitute a honeycomb pattern (a) within dense fibrosis (b) beneath the pleura (c). Scar obliterates normal alveolar architecture. d = fibroblastic foci, e = smooth muscle hyperplasia. (d) Photomicrograph (original magnification, x50; hematoxylin-eosin stain) shows active fibroblastic foci of myxoid connective tissue (d), which form nodules projecting into alveolar-sized air space. Pneumocytes are hyperplastic.