Histologic features of nonspecific interstitial pneumonia

Key histologic features

Cellular pattern*

Mild to moderate interstitial chronic inflammation

Type II pneumocyte hyperplasia in areas of inflammation

Fibrosing pattern*

Dense or loose interstitial fibrosis lacking the temporal heterogeneity pattern and/or patchy features of UIP

Lung architecture may appear lost on examination of H&E-stained section, but is relatively preserved with elastin stains

Interstitial chronic inflammation - mild or moderate

Pertinent negative findings

Cellular pattern

Dense interstitial fibrosis: absent

Organizing pneumonia: absent or not prominent

Diffuse severe alveolar septal inflammation: absent

Fibrosing pattern

Temporal heterogeneity pattern: fibroblastic foci with dense fibrosis are inconspicuous or absent - this is especially important in cases with patchy involvement and subpleural or paraseptal distribution

Both patterns

Acute lung injury pattern, especially hyaline membranes: absent

Eosinophils: inconspicuous or absent

Granulomas: inconspicuous or absent

Viral inclusions and organisms on special stains: not present

* There is a spectrum from cellular to fibrosing patterns, with some cases showing a combination of cellular and fibrosing features.
UIP: usual interstitial pneumonia; H&E: hematoxylin and eosin.

Graphic 81034 Version 3.0

خرید پکیج

Histologic features of nonspecific interstitial pneumonia