UIP in chronic nitrofurantoin toxicity, low magnification
UIP in chronic nitrofurantoin toxicity, low magnification

UIP in chronic nitrofurantoin toxicity. This is a low magnification image of a lung biopsy from a patient who developed respiratory symptoms following 1 year of nitrofurantoin therapy. There are regions of variable consolidation of lung with parenchymal fibrosis (best seen on the left side of this image) and patchy areas of spared lung (subpleurally on the right side of the image). This "variegated" appearance at scanning magnification is one of the hallmarks of the UIP pattern of pulmonary fibrosis. The small blue foci present here beneath the pleura are lymphoid aggregates. Chronic drug reactions rarely produce a picture closely resembling UIP microscopically. Even when fibrosis is "temporally heterogeneous" (as in this case) there are often features such as lymphoid aggregates and inconsistent peripheral distribution of dense fibrosis that are atypical of UIP. Hematoxylin and eosin stain 12X original magnification. Click to next image for high magnification.