Prognostic Implications of Histologic Patterns in Multiple Surgical Lung Biopsies from Patients with Idiopathic Interstitial Pneumonias

Study objectives: To determine the prevalence and prognostic significance of histologic discordance in multiple lung biopsy specimens obtained from patients investigated for suspected cryptogenic fibrosing alveolitis (CFA)/idiopathic pulmonary fibrosis (IPF). Methods and results: Between 1984 and 2001, 64 patients undergoing investigation for CFA/IPF were identified in whom multiple biopsies were performed that showed either a pattern of usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP). These cases were classified into three groups: concordant UIP-UIP (n = 25, 39.1%), discordant UIP-NSIP (n = 8,12.5%), and concordant NSIP-NSIP (n = 31, 48.4%). The discordant UIP group had survival, clinical, and physiologic features similar to those of the concordant UIP group, and prognosis in both concordant and discordant UIP groups was significantly worse than that of the concordant NSIP group (p = 0.02 and p = 0.04, respectively). The age of the concordant UIP group was higher than that of the concordant NSIP group, with the mean age of the discordant group being intermediate. There were no significant differences among the three groups in smoking history, duration of dyspnea, presence or absence of crackles, FVC, diffusion capacity of the lung for carbon monoxide, or PaO₂. Conclusions: Patients with discordant UIP-NSIP results on multiple biopsies show clinical behavior similar to those with concordant UIP-UIP and should be regarded as having CFA/IPF in the correct clinical context, rather than "idiopathic NSIP" for the purposes of management. Multiple biopsies should be considered in all patients in order to improve the prognostic information provided by lung biopsy.