(No Copyright)"Usual" Interstitial
Pneumonia
Usual interstitial pneumonia (idiopathic pulmonary fibrosis). In the right half of the photo the lung is nearly normal. On the left it is scarred and alveoli lost. The arrow shows a small focus of active fibroblasts in a young-looking, proteoglycan-rich matrix. Typical UIP shows burned out scarring and honeycombing coexisting with small foci of active, ongoing fibrosis.
