A Case of Acute Fibrinous and Organizing Pneumonia

Abstract

Acute fibrinous and organizing pneumonia (AFOP) is a histological pattern consisting of prominent intra-alveolar fibrin and organizing pneumonia, with out hyaline membranes or prominent eosinophilia. The clinical manifestations of AFOP resemble those of acute lung injury such as acute interstitial pneumonia (AIP). However, the classic histological patterns of AFOP differ from diffuse alveolar damage (DAD), bronchiolitis obliterans with organizing pneumonia (BOOP) or acute eosinophilic pneumonia (AEP). The characteristic intra-alveolar fibrin ball and lack of classic hyaline membrane are the predominant histological features of AFOP. Although some reports suggest that its clinical course is less catastrophic than DAD, the clinical entity that distinguishes AFOP from DAD has not been established. We present a case of pathologically demonstrated AFOP in a 79-year-old man. The radiological findings of our case were similar to those of DAD, presented with diffuse bilateral lung infiltrations. However, despite the rapid development of respiratory failure, the patient had a better response and outcome to steroid therapy than what would be expected for DAD.