OBJECTIVETo study the pathologic features, differential diagnosis and role of open lung biopsies (OLB) in usual interstitial pneumonia (UIP).

METHODThe authors reviewed the pathologic, clinical and radiologic features of five cases of UIP (one autopsy case and four OLB cases), with follow-up information.

RESULTSThe typical histologic features were a non-uniform distribution of alveolar inflammation, fibroblastic foci, interstitial fibrosis and honeycomb change. There also was associated metaplasia of bronchiolar epithelium, type II pneumocyte hyperplasia and accumulation of alveolar macrophages.

CONCLUSIONSCharacteristically, UIP exhibits temporal heterogeneity under low-power light microscopy, which includes changes in both the early and end stages. Open lung biopsy is an important diagnostic adjunct for suitable patients with atypical radiologic features on computerized tomography. Correlation between clinical, radiologic and pathologic findings is also essential for a correct diagnosis.