<prompt> A 40-year-old woman with leukemia is treated with chemotherapy. During treatment she develops increasing cough and shoness of breath. A chest X-ray shows diffuse lung infiltrates. Sputum cultures are negative and the patient does not respond to routine antibiotic therapy. An open lung biopsy is diagnosed by the pathologist as viral pneumonia. Which of the following histopathologic findings would be expected in the lungs of this patient?Clusters of epithelioid macrophagesConfluent areas of caseous necrosisFibrous scarring of lung parenchymaHyaline membranes and interstitial inflammation  <response>: Viral infections of the pulmonary parenchyma produce diffuse alveolar damage DAD and interstitial pneumonia. Necrosis of type I pneumocytes and the formation of hyaline membranes result in an appearance that is indistinguishable from DAD in other settings. The other choices are not characteristic of interstitial pneumonia.Fibrous scarring of lung parenchyma may be a late complication of some forms of this disorder. 