Airway-centered interstitial fibrosis - A distinct form of aggressive diffuse lung disease

We describe 12 patients with a form of interstitial lung disease characterized pathologically by small airway-centered interstitial fibrosis and metaplastic bronchiolar epithelium extending around and often linking fibrotic and sometimes heavily muscularized bronchioles. Clinically, patients presented with chronic cough and progressive dyspnea. One was a current light smoker and two were ex-smokers. In 8 patients, a history of possible inhalational exposures, including wood smoke, birds, cotton, pasture, chalk dust, agrochemical compounds, and cocaine use, was elicited. Pulmonary function tests showed moderate to severe physiologic abnormalities, in most instances indicating a restrictive lung disease with decreased peripheral flow rates. Chest radiographs revealed predominantly diffuse reticulonodular infiltrates in the central lung fields, with thickening of the bronchial walls and decreased lung volumes. Chest computed tomography demonstrated peribronchovascular fibrosis and interstitial thickening. Bronchoalveolar lavage showed a mild increase in lymphocytes in 4 subjects. Patients were treated with corticosteroids and bronchodilators. Follow-up data were available in 10 patients. In 5 patients, the disease progressed and 4 of them died. Two patients remained stable and 3 improved or healed. We propose that these findings represent a distinct airway-centered disease that mostly behaves as an interstitial lung disease and may exhibit a poor outcome.