The prognostic significance of the histologic pattern of interstitial pneumonia in patients presenting with the clinical entity of cryptogenic fibrosing alveolitis

Lone cryptogenic: fibrosing alveolitis (CFA) is a progressive interstitial lung disease, with a median survival of 3 to 6 yr from the onset of dyspnea . CFA can be subdivided into prognostically significant histopathologic pat terns, including nonspecific interstitial pneumonia (NSIP). We reviewed 78 patients with a clinicopathologic diagnosis of CFA, biopsied between 1978 a nd 1989, to evaluate the prevalence and prognostic significance of these hi stopathologic: patterns, in particular NSIP. Biopsy appearances were reclas sified by two pulmonary histopathologists as usual interstitial pneumonia ( UIP) (47%), NSIP (36%), or desquamative interstitial pneumonia (DIP)/respir atory bronchiolitis-associated interstitial lung disease (RBILD) (17%). The kappa coefficient of agreement between pathologists was 0.49. In 67 cases, follow-up was complete to death or 10 yr after biopsy, with 50 deaths duri ng a median follow-up of 42 mo (UIP, 89%; NSIP, 61%, DIP/RBILD, 0%). Surviv al was highest in DIP/RBILD and higher in NSIP than UIP, p < 0.0005. When a nalysis was confined to patients with UIP or NSIP, the mortality of UIP rem ained higher, p < 0.01, but the 5-yr survival in patients with fibrotic NSI P was only 45%, indicating that this histologic appearance is often associa ted with a poor outcome. A response to treatment was more frequent in DIP/R BILD than in NSIP (p < 0.01) or UIP (p < 0.0005). This study confirms the p rognostic: value of subclassifying patients with CFA according to histopath ologic pattern. However, in patients with clinically typical CFA, a histolo gic diagnosis of fibrotic NSIP needs to be interpreted with caution and doe s not necessarily denote a good outcome.