Figure 1

Transbronchial biopsies in three different patients with a final diagnosis of UIP. A) An area of scarring/honeycombing at the left, showing architectural abnormal lung with fibrosis and enlarged airspaces bordered by bronchiolar epithelium. Mucostasis is frequently present but can be absent, like here. Hematoxylin-Eosin, 100X. B) Higher magnification showing enlarged airspaces with bronchial metaplasia in the absence of mucus. Hematoxylin-Eosin, 20X. C) An area of fibrosis with a patchy character, in which collagen-type interstitial fibrosis is present adjacent to relatively normal alveoli. Hematoxylin-Eosin, 100X. D) A fibroblast focus, consisting in a small, dome-shaped collection of myofibroblasts within myxoid stroma, adjacent to fibrotic lung tissue. Fibroblast foci are frequently covered by hyperplastic pneumocytes, like here. Hematoxylin-Eosin, 200X.