Usual interstitial pneumonia pattern

(A) Patchy fibrosis with remodeling of the lung architecture shows a striking subpleural distribution. Interstitial chronic inflammation is mild with a few lymphoid aggregares. Areas of "normal" lung are present that lack active lesions of other interstitial lung disorders. (B) There is marked fibrosis consisting of dense collagenous scarring with remodeling of the lung architecture and cystic changes. (C) The dense collagenous scar is juxtaposed with a fibroblastic focus of loose organizing connective tissue.