Clinical significance of respiratory bronchiolitis on open lungbiopsy and its relationship to smoking related interstitial lungdisease

摘要

BACKGROUND—Respiratory bronchiolitis-associated interstitial lung disease (RBILD) is a rare form of interstitial lung disease which may present in similar fashion to other types of chronic interstitial pneumonia. The purpose of this study was to undertake a clinicopathological review of 10 patients with RBILD and to examine the clinical and imaging data related to its histopathological pattern, in particular the relationship of RBILD to smoking.
METHODS—Thirteen out of 168 retrospectively reviewed patients, from whom biopsy specimens were taken for suspected diffuse lung disease, were identified with a histopathological pattern of RBILD. Three cases were rejected as follow up data were unavailable. The 10remaining cases constituted the study group and both clinical and imaging data were collected from patients' notes and referring physicians.
RESULTS—Histopathologically, four cases of RBILD overlapped with the pattern of desquamative interstitial pneumonitis (DIP) and nine also had microscopic evidence of centrilobular emphysema. Nine patients were smokers, ranging from 3 to 80 pack years. The one non-smoker had an occupational exposure to the fumes of solder flux. The sex distribution was equal with an agerange of 32-65 years. Two patients were clubbed. Lung function testsshowed both restrictive and obstructive patterns together with severereductions in carbon monoxide transfer factor in seven patients. Chestradiographs showed reticular or reticulonodular infiltrates in fivepatients and a ground glass pattern in two. CT scans were consistentwith either DIP or RBILD in six of eight patients. Although sevenpatients remained stable or improved, either with or without treatment, three patients deteriorated.
CONCLUSIONS—This studyadds weight to the hypothesis that smoking can cause clinicallysignificant interstitial lung disease, with deterioration in pulmonaryfunction despite treatment. Given the overlapping histopathologicalpatterns of RBILD and DIP and their strong association with smoking,the term "smoking related interstitial lung disease" is suggestedfor those patients who are smokers.