Findings of surgical lung biopsy (SLB) are important in categorizing patients with idiopathic interstitial pneumonia (IIP). We investigated whether histologic variability would be evident in SLB specimens from multiple lobes in patients with IIP. SLBs from 168 patients, 109 of whom had multiple lobes biopsied, were reviewed by three pathologists. A diagnosis was assigned to each lobe. A different diagnosis was found between lobes in 26% of the patients. Patients with usual interstitial pneumonia (UIP) in all lobes were categorized as concordant for UIP (n = 51) and those with UIP in at least one lobe were categorized as discordant for UIP (n = 28). Patients with nonspecific interstitial pneumonia (NSIP) in all lobes were categorized as having fibrotic (n = 25) or cellular NSIP (n = 5). No consistent distribution of lobar histology was noted. Patients concordant for UIP were older (63 +/- 9 [mean +/- SD] yr; p < 0.05 as compared with all other groups) than those discordant for UIP (57 +/- 12 yr) or with fibrotic NSIP (56 +/- 11 yr) or cellular NSIP (50 +/- 9 yr). Semiquantitative high-resolution computed tomography demonstrated a varied profusion of fibrosis (p < 0.05 for all group comparisons), with more fibrosis in concordant UIP (2.13 +/- 0.62) than in discordant UIP (1.42 +/- 0.73), fibrotic NSIP (0.83 +/- 0.58), or cellular NSIP (0.44 +/- 0.42). Survival was better for patients with NSIP than for those in both UIP groups (p < 0.001), although survival in the two UIP groups was comparable (p = 0.16). Lobar histologic variability is frequent in patients with IIP, patients with a histologic pattern of UIP in any lobe should be classified as having UIP.

No abstract

Patients with idiopathic interstitial pneumonias (IIPs) can be subdivided into groups based on the histological appearance of lung tissue obtained by surgical biopsy. The quantitative impact of histological diagnosis, baseline factors and response to therapy on survival has not been evaluated.Surgical lung biopsy specimens from 168 patients with suspected IIP were reviewed according to the latest diagnostic criteria. The impact of baseline clinical, physiological, radiographic and histological features on survival was evaluated using Cox regression analysis. The predictive value of honeycombing on high-resolution computed tomography (HRCT) as a surrogate marker for usual interstitial pneumonia (UIP) was examined. The response to therapy and survival of 39 patients treated prospectively with high-dose prednisone was evaluated.The presence of UIP was the most important factor influencing mortality. The risk ratio of mortality when UIP was present was 28.46 (95% confidence interval (CI) 5.5-148.0; p=0.0001) after controlling for patient age, duration of symptoms, radiographic appearance, pulmonary physiology, smoking history and sex. Honeycombing on HRCT indicated the presence of UIP with a sensitivity of 90% and specificity of 86%. Patients with nonspecific interstitial pneumonia were more likely to respond or remain stable (9 of 10) compared to patients with UIP (14 of 29) after treatment with prednisone. Patients remaining stable had the best prognosis. The risk ratio of mortality for stable patients compared to nonresponders was 0.32 (95% CI 0.11-0.93; p=0.04) in all patients and 0.33 (95% CI 0.12-0.96; p=0.04) in patients with UIP.The histological diagnosis of usual interstitial pneumonia is the most important factor determining survival in patients with suspected idiopathic interstitial pneumonia. The presence of honeycombing on high-resolution computed tomography is a good surrogate for usual interstitial pneumonia and could be utilized in patients unable to undergo surgical lung biopsy. Patients with nonspecific interstitial pneumonia are more likely to respond or remain stable following a course of prednisone. Patients remaining stable following prednisone therapy have the best prognosis. Eur Respir J 2002; 19: 275-283. This study was supported in part by National Institutes of Health (NIH) National Heart, Lung, and Blood Institute (NHLBI) Grant #P50HL46487, NIH/NCRR 3 MO1 RR00042-33S3, NIH/NIA P60 AG08808-06 and NHLBI, 1 K24 HL04212-01.A recent consensus statement has proposed that idiopathic interstitial pneumonias (IIPs) be divided into histopathological subsets that differ in prognosis and response to therapy [1]. These subsets include usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP), respiratory bronchiolitis interstitial lung disease (RBILD), desquamative interstitial pneumonia (DIP), and others [2,3]. This approach, by definition, requires surgical lung biopsy (SLB).The clinical features of IIP are nonspecific. Reliable noninvasive markers of the above patholog...