[Organizing pneumonia associated with the use of pegylated interferon alfa].

Organizing pneumonia is a well-differentiated clinical and histologic entity whose onset is usually subacute with respiratory symptoms and pulmonary infiltrates. Its origin may be unknown (cryptogenic) or it may be associated with various medical conditions, infectious diseases, or drugs. Diagnosis is confirmed by the presence of foci of organizing pneumonia in lung biopsy specimens. Our patient was a 49-year-old man infected with the hepatitis C virus who was receiving pegylated interferon alfa-2b. He presented with dry cough, fever, dyspnea, and ground glass pulmonary infiltrates. After an open lung biopsy, he was diagnosed with organizing pneumonia. When pegylated interferon was discontinued and corticosteroids started, the symptoms and pulmonary infiltrates disappeared. To our knowledge, this is the second report of organizing pneumonia related to pegylated interferon alfa-2b.