Bronchiolitis. Pathologic considerations

Am J Clin Pathol. 1998 Jan;109(1):101-9. doi: 10.1093/ajcp/109.1.101.


Bronchiolitis represents a cellular and mesenchymal reaction involving bronchioles. The interplay between the cellular infiltrate and the mesenchymal reaction affects the lumen size, lamina propria, muscular layer, and bronchiolar adventitia. The result is a variety of clinical, radiologic, and functional patterns of bronchiolar disease. The anatomy of the small airways is discussed, and a pathologic classification applicable to the surgical pathology of bronchiolitis is presented. The classification is practical and includes asthma, chronic obstructive pulmonary disease, cellular bronchiolitis, respiratory bronchiolitis, respiratory bronchiolitis-associated interstitial lung disease, bronchiolitis obliterans (including bronchiolitis obliterans with intraluminal polyps and constrictive bronchiolitis), dust-related small airway fibrosis, and (postinflammatory) bronchiolar scarring and peribronchiolar fibrosis.

Publication types

  • Review

MeSH terms

  • Asthma / pathology
  • Bronchi / anatomy & histology
  • Bronchi / pathology
  • Bronchiolitis / immunology
  • Bronchiolitis / pathology*
  • Bronchiolitis Obliterans / pathology
  • Child, Preschool
  • Cryptogenic Organizing Pneumonia / pathology
  • Fibrosis / pathology
  • Humans
  • Inflammation / pathology*
  • Lung Diseases, Obstructive / pathology
  • Metaplasia / pathology