[Pathologic findings both before and after steroid therapy in a case of desquamative interstitial pneumonia]

A 62-year-old man was admitted to our hospital because of dyspnea on effort. Histological findings from video-assisted thoracoscopic surgical biopsy were desquamative interstitial pneumonia (DIP). Two months after the introduction of steroid therapy, the patient underwent right middle lobe lobectomy for primary lung cancer. The histologic findings in this lobe revealed non-specific interstitial pneumonia, not characteristic of DIP. This case was the first in which histologic examination revealed DIP both before and after steroid therapy.