A case of smoking-related interstitial lung disease with a histopathologic pattern overlapping that of usual interstitial pneumonia and respiratory bronchiolitis

A 60-year-old man was admitted to Fukuoka-Higashi Medical Center because of an abnormal shadow on a chest radiograph. He was a current smoker and had been smoking since many years. We performed video-assisted thoracoscopic lung biopsy (VATS) for definitive histological diagnosis. Histopathological examination of a lung specimen obtained from the left lingular region showed a pattern consistent with that of usual interstitial pneumonia (UIP) : however, a specimen from the left S⁹ showed patterns consisten with those of both respiratory bronchiolitis (RB) and UIP. The findings on chest radiography and pulmonary functioning of the patient improved when he stopped smoking. On the basis of these findings, we diagnosed this case as smoking-related interstitial lung disease (SRILD) showing a histopathologic pattern overlapping that of UIP and RB.