Destructive Bronchiolitis: A Characteristic Pathological Feature Of Interstitial Lung Disease Preceding The Onset Of Rheumatoid Arthritis

Aims and Objectives: Interstitial lung disease (ILD) is the most critical disease in patients with rheumatoid arthritis (RA). Some patients with an initial diagnosis of idiopathic interstitial pneumonias (IIPs) subsequently develop RA in clinical course, but the details are unknown. We evaluated the features of ILD preceding the onset of RA. Methods: We retrospectively reviewed 883 patients with IIPs who underwent surgical lung biopsy at our hospital from 2004 to 2018 and extracted patients who developed RA after IIPs diagnosis. HRCT and histological patterns were applied with 2018 ATS/ERS guideline. We evaluated radiological and pathological features of parenchymal and airway involvement in these patients, compared with those of IPF/UIP patients. Results: There were 10 patients who developed RA after IIPs diagnosis. The median age was 59 years and 7 patients were female. None of patients were anti-CCP antibody-positive at the time of biopsy, and the median time from IIPs diagnosis to RA onset was 50 months. In radiological analysis, indeterminate for UIP pattern was the most popular. During the clinical course, cystic lesions progressed in size and extent. Pathology revealed cellular and destructive bronchiolitis (inflammatory cell infiltration with destruction of bronchiolar wall), consequent to cystic change of a lobule in 8 patients. Conclusions: In ILD preceding the onset of RA, cellular and destructive bronchiolitis may develop to cystic change of the lobules. Patients in IIPs with these characteristics need to be under observation for the development of RA.