Transbronchial Biopsy and Usual Interstitial Pneumonia: A Step Backward in Disease Management?

Abstract

We read with interest the article by Berbescu et al (May 2006),1Berbescu EA Katzenstein A-L Snow JL et al.Transbronchial biopsy in usual interstitial pneumonia.Chest. 2006; 129: 1126-1131Abstract Full Text Full Text PDF PubMed Scopus (122) Google Scholar who attributed a role for transbronchial lung biopsy (TBLB) in the diagnosis of usual interstitial pneumonia (UIP). Their conclusions raise serious issues, aside from the potential bias in this unblinded retrospective study. Irrespective of operator expertise, TBLB has inherent sampling errors, particularly in patients with established lung fibrosis. Small specimen size makes TBLB a “histopathologist's nightmare,” with difficulty in distinguishing different patterns within the spectrum of diffuse parenchymal lung diseases; patients may have overlapping histologic features. Berbescu et al1Berbescu EA Katzenstein A-L Snow JL et al.Transbronchial biopsy in usual interstitial pneumonia.Chest. 2006; 129: 1126-1131Abstract Full Text Full Text PDF PubMed Scopus (122) Google Scholar failed to mention sample size. Adequate biopsy size, ideally a 4-cm maximum diameter when inflated, and a depth of at least 1 to 1.5 cm,2British Thoracic Society. Diagnosis and assessment of diffuse parenchymal lung disease.Thorax. 1999; 54: S1-S14Crossref PubMed Scopus (26) Google Scholar are critical to identify potential prognostic markers, such as the degree of alveolar space granulation tissue deposition and the extent of early connective tissue formation within the fibroblastic foci, in patients with UIP; such factors may also impact on treatment outcome.3Nicholson AG Fulford LG Colby TV et al.The relationship between individual histologic features and disease progression in idiopathic pulmonary fibrosis.Am J Respir Crit Care Med. 2002; 166: 173-177Crossref PubMed Scopus (249) Google Scholar, 4Hunninghake GW Zimmerman MB Schwartz DA et al.Utility of a lung biopsy for the diagnosis of idiopathic pulmonary fibrosis.Am J Respir Crit Care Med. 2001; 164: 193-196Crossref PubMed Scopus (467) Google Scholar An additional inevitable crush effect, a failure to penetrate beyond the peribronchial sheath, and friable tissue disintegration preclude proper histologic assessment. In the present study,1Berbescu EA Katzenstein A-L Snow JL et al.Transbronchial biopsy in usual interstitial pneumonia.Chest. 2006; 129: 1126-1131Abstract Full Text Full Text PDF PubMed Scopus (122) Google Scholar apart from the patient in case 10, sampling is from the same affected lobe. Temporal heterogeneity in patients with idiopathic interstitial pneumonias is a critical histologic hallmark; TBLB samples, especially from the same site, are insufficient to determine the “concordant” and “discordant” patterns between UIP and nonspecific interstitial pneumonia, which has important clinical outcome implications.5Flaherty KR Travis WD Colby TV et al.Histopathologic variability in usual and nonspecific interstitial pneumonias.Am J Respir Crit Care Med. 2001; 164: 1722-1727Crossref PubMed Scopus (570) Google Scholar Berbescu et al1Berbescu EA Katzenstein A-L Snow JL et al.Transbronchial biopsy in usual interstitial pneumonia.Chest. 2006; 129: 1126-1131Abstract Full Text Full Text PDF PubMed Scopus (122) Google Scholar attempted to describe some histologic features that may be helpful in diagnosing UIP. We would argue that the evaluation of these findings in TBLB samples may rest on the expertise of the local service pathologist. Most of the described changes, which involve some secondary in situ fibrogenic process, are nonspecific for UIP and can be found in patients with other lung conditions.