Six patients with specific pulmonary diseases had pulmonary tissue surgically resected for diagnostic purposes. All six cases were characterized by space-occupying lesions surrounded by a peculiar reaction of the pulmonary parenchyma indistinguishable from desquamative interstitial pneumonia. If small biopsies from these areas had been taken, a diagnosis of desquamative interstitial pneumonia would have been made, and the underlying process would have gone undetected. These cases corroborate even further the concept that desquamative interstitial pneumonia is a pattern of pulmonary reaction, rather than a well-defined disease entity. Furthermore, it seems advisable to make the dianosis of desquamative interstitial pneumonia only when other conditions have been carefully ruled out by thorough clinical and pathologic investigations.