[A case of lung adenocarcinoma showing diffuse air-space consolidation with idiopathic interstitial pneumonia].

Routine chest radiography demonstrated abnormal opacities in the right lower lung field of a 54-year-old man with idiopathic interstitial pneumonia. A high-resolution chest CT scan showed diffuse air-space consolidation in the right lower lung with replacement of a honeycomb area. The diagnosis was adenocarcinoma, and a right lower lobectomy was performed. Histopathologic examination showed moderately differentiated adenocarcinoma and the pathological stage was T3 N0 M0 (Stage IIB). About 1 year later, the cancer recurred with diffuse air-space consolidation in the whole of the right lung and the left middle and lower lung, which resulted in the patient's death. It was difficult to discriminate between an acute change for the worse of idiopathic interstitial pneumonia and a recurrence of lung cancer on the basis of the CT findings in this patient. It is important to elucidate the CT features of lung cancer associated with idiopathic interstitial pneumonia.