[A case of bronchiolitis obliterans organizing pneumonia in a patient with rheumatoid arthritis who responded to corticosteroid and immunosupressant therapy].

A 56-year-old man with rheumatoid arthritis was admitted to our hospital with dyspnea on exertion, fever and right chest pain. Chest X-ray showed bilateral, predominantly lower interstitial shadows and right pleural effusion. Open lung biopsy specimen showed bronchiolitis obliterans organizing pneumonia (BOOP) with prominent alveolitis, and corticosteroid therapy was introduced. Because the patient showed little response to corticosteroids, an immunosupressant (cyclophosphamide) was added. There was marked clinical, physiological and roentgenographic improvement in response to combined therapy. The therapeutic response of some BOOP patients seems to vary according to its pathogenesis and pathological findings, and these should be taken into consideration in the selection of therapeutic strategies.