Peribronchiolar metaplasia (PBM) is a histologic lesion consisting of peribronchiolar metaplasia (PBM) of bronchiolar-type epithelium. Although widely recognized, PBM has received little attention in the pathologic literature and is not known to have clinical significance. We identified 15 cases in which PBM was the only major histologic finding in surgical lung biopsies from patients with interstitial lung disease (PBM-ILD), and we reviewed the clinical, imaging, and pathologic findings. The mean age was 57 years (range, 44-74 years) with 13 females and 2 males. One patient had been a welder with fume and asbestos exposure; another had pigeon exposure. Smoking history was available for 13 patients: three current smokers, one cocaine user, two former smokers, and seven never smokers. Three patients had collagen vascular disease. One had elevated serum antinuclear antibody titers. Pulmonary function data were available for 10 patients: one obstructive, five restrictive, two mixed obstructive and restrictive, and two normal. Computerized tomography in 7 patients showed mosaic attenuation in 3 patients and air trapping in 1 patient; no bronchiectasis, septal lines, or honeycombing were seen in any cases. All 11 patients with available follow-up are alive; 4 of them have experienced symptomatic improvement (follow-up, 0.6-6.9 years; mean, 2.4 years). PBM was found focally in other interstitial lung diseases, which were assessed for this lesion: 59% of usual interstitial pneumonia (17 of 29), 50% of nonspecific interstitial pneumonia (10 of 20), desquamative interstitial pneumonia (3 of 6), hypersensitivity pneumonitis (9 of 18), and 11% of respiratory bronchiolitis (2 of 18). In summary, PBM is a common histologic finding in various interstitial lung disorders. It is rarely the sole major lung biopsy finding in patients presenting with interstitial lung disease (PBM-ILD). Patients are mostly older women, with mild symptoms and CT findings. Survival appears to be favorable.
From the *Laboratory of Population Genetics, National Cancer Institute, Bethesda, MD and †Department of Pulmonary and Mediastinal Pathology, Armed Forces Institute of Pathology, Washington, DC; ∥Department of Radiology, Armed Forces Institute of Pathology, Washington, DC; ‡Department of Laboratory Medicine, Mayo Clinic Scottsdale, Scottsdale, AZ; §Department of Pulmonary Medicine, University of Michigan, Ann Arbor, MI; ¶Pulmonary and Critical Care Medicine, National Heart, Lung, and Blood Institute, Bethesda, MD and #Department of Radiology, University of Michigan, Ann Arbor, MI. The current affiliation for Dr. Fukuoka is Department of Pathology, Toyama Medical and Pharmaceutical University Hospital, Toyama, Japan. The current affiliation for Dr. Travis is Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY.
Reprints: William D. Travis, MD, Department of Pathology, Memorial Sloan Kettering Cancer Center,1275 York Ave, New York, NY 10021 (e-mail: firstname.lastname@example.org).