Acute fibrinous and organising pneumonia (AFOP) was recently described as an unusual pattern of diffuse lung disease. Particular characteristics make the differential diagnosis with the well recognised clinical patterns of diffuse alveolar damage, cryptogenic organising pneumonia or eosinophilic pneumonia. The lack of hyaline membranes, the presence of intra-alveolar fibrin, absence of noticeable eosinophils and patchy distribution suggests that AFOP define a distinct histological pattern. The authors describe the case of a woman diagnosed with AFOP after surgical lung biopsy, in association with primary biliary cirrhosis. The patient presented dyspnoea, fatigue, dry cough and thoracic pain. The CT scan showed bilateral patchy infiltrates predominantly in the lower lobes. Flexible bronchoscopy and subsidiary techniques were inconclusive and biopsy through video-assisted thoracoscopic surgery led to anatomopathological diagnosis of AFOP. The patient is having a good clinical response to prednisone.