Fig. (2) Usual interstitial pneumonia (UIP) as manifestation of IgG4-related disease. Low power (A and B) and high power (C and D) views of the surgical lung biopsy show typical distribution of fibrosis along pleura and interlobular septa with spared centrilobular areas and fibroblastic foci (arrows). Superimposed is a prominent lymphoplasmacytic inflammatory infiltrate involving pleura and interstitium (arrowheads). [Hematoxylin Eosin, original x20 (A and B) and x200 (C and D)]