Interferon-related bronchiolitis obliterans organizing pneumonia.

We present an unusual case of a patient with chronic hepatitis C who experienced dyspnea, fever, and cough after 2 1/2 months' treatment with interferon. His radiograph demonstrated diffuse pulmonary infiltrates and bronchoalveolar lavage fluid showed an increase in lymphocytes, especially CD8-positive cells. The lung biopsy findings were bronchiolitis obliterans organizing pneumonia (BOOP). The pulmonary symptoms disappeared and the chest radiograph became normal after interferon therapy was discontinued and corticosteroid therapy was given. Interferon is suspected to be responsible for the BOOP.