Case 281

History An 18-year-old man was diagnosed with precursor B-cell lymphoblastic leukemia and underwent transplantation of hematopoietic stem cells from his human leukocyte antigen-matched sister 1 year prior to admission. He was admitted to evaluate progressive shortness of breath and dry cough of 1-month duration. He did not report fever, night sweats, or hemoptysis. Physical examination revealed he was afebrile and had normal pulse oxygen saturation. The examination revealed crepitation on palpation of the anterior neck, expiratory wheezes, and crackles heard at auscultation of bases of both lungs. Extensive maculopapular rash on the skin was consistent with graft-versus-host disease (GVHD). Laboratory tests revealed elevated liver transaminase and bilirubin levels that were attributed to liver GVHD. Nonenhanced thin-section CT of the chest was performed (Figs 1-5).