Stanford School of Medicine

Surgical Pathology Criteria

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Respiratory Bronchiolitis Associated Interstitial Lung Disease


  • Bronchiolocentric accumulations of macrophages with symptomatic interstitial lung disease

Diagnostic Criteria

  • Clinical
    • Essentially all affected patients are smokers
    • Adults most are 30-60
    • Identical histologic changes may be seen in asymptomatic smokers; the diagnosis requires clinically significant disease
      • Chronic dyspnea, cough
      • Pulmonary function tests
        • Usually mild restrictive or mixed restrictive/obstructive
        • Decreased diffusing capacity in the absence of airflow obstruction
    • Good response to smoking cessation
  • High resolution computed tomography (HRCT)
    • Centrilobular nodules
    • Ground glass opacities
  • Histopathologic features
    • Patchy bronchiolocentric process
      • Intervening lung tissue is not affected
    • Intralumenal macrophage accumulation centered on respiratory bronchioles
      • Macrophages fill bronchiole and adjacent alveoli
      • Macrophages contain finely granular golden brown pigment
        • Iron positive
        • Termed "smokers macrophages"
    • Mild to moderate fibrosis may surround the bronchiole and involve adjacent alveolar septa
      • Pulmonary architecture is preserved
    • Mild interstitial infiltrate of histiocytes and plasma cells may be present in the same regions
    • Reactive alveolar lining cells may be present
    • Occurring in smokers' lungs, other clinicopathologic disorders such as chronic bronchitis and emphysema are frequently present
  • All other types of interstitial lung disease must be ruled out
    • Features of other types of interstitial lung disease should not be present
    • The following features should not be seen
      • Granulomas or giant cells
      • Foreign material other than anthracotic pigment
      • More than rare eosinophils
      • Evidence of infection
  • May form a spectrum with desquamative interstitial pneumonia
    • Patchy (RBAILD) vs. diffuse (DIP) airspace involvement by macrophages

Gerald J Berry MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting/updates: 11/20/10

Differential Diagnosis

Respiratory Bronchiolitis Associated Interstitial Lung Disease Usual Interstitial Pneumonia
Fibrosis does not destroy architecture, no honeycombing Fibrosis destroys architecture, honeycombing is prominent
No fibroblastic foci Frequent fibroblastic foci
Air spaces filled with macrophages Filling of airspaces with macrophages is not seen
HRCT shows centrilobular nodule pattern HRCT shows honeycombing, peripheral accentuation


Respiratory Bronchiolitis Associated Interstitial Lung Disease Desquamative Interstitial Pneumonia
Patchy Diffuse pulmonary involvement
Intra-alveolar macrophages only focally present Diffuse intra-alveolar macrophages
Mild pneumocyte hyperplasia Prominent pneumocyte hyperplasia
Peribronchiolar thickening Interstitial thickening


Respiratory Bronchiolitis Associated Interstitial Lung Disease Langerhans Cell Histiocytosis
Predominantly intra-alveolar process Predominantly interstitial process, intra-alveolar macrophages only focally present
Eosinophils rare Eosinophils may be numerous
No cystic change Cystic change frequent
Lacks scarring Produces stellate scars
Histiocytes with round nuclei Histiocytes with folded nuclei
Macrophages CD1a and langerin negative Langerhans cells positive for CD1a and langerin
Both are highly associated with smoking, thus foci or respiratory bronchiolitis are expected to be present in the lung tissue of cases of Langerhans cell histiocytosis


Respiratory Bronchiolitis Associated Interstitial Lung Disease Hypersensitivity Pneumonitis
Lacks granulomas and giant cells Granulomas and giant cells generally present but may be infrequent in late stage
Smoking history only Possible exposure history
May develop mild-moderate peri-bronchiolar fibrosis but architecture is preserved May develop significant fibrosis with honeycomb change


  • Respiratory bronchiolitis associated interstitial lung disease (RBAILD) can be diagnosed only in the presence of clinical disease and in the absence of patterns of other interstitial lung diseases
    • Acute and nonspecific interstitial lung diseases are diffuse processes and lack the focality of RBAILD
    • Cryptogenic organizing pneumonia is also bronchiolocentric but is characterized by intralumenal organization, rather than the interstitial fibrosis and intralumenal macrophages of RBAILD
    • Chronic pulmonary hemorrhage leads to macrophages filled with coarse hemosiderin, not the fine granularity of those in RBAILD

Classification / Lists

Smoking Related Lung Diseases

Idiopathic Interstitial Lung Diseases

Other Diffuse Parenchymal Lung Diseases



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  • American Thoracic Society; European Respiratory Society. ATS/ERS International Multidisciplinary Consensus Classification of the Idiopathic Interstitial Pneumonias. This joint statement of the American Thoracic Society (ATS), and the European Respiratory Society (ERS) was adopted by the ATS board of directors, June 2001 and by the ERS Executive Committee, June 2001. Am J Respir Crit Care Med. 2002 Jan 15;165(2):277-304.
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  • Yousem SA. Respiratory bronchiolitis-associated interstitial lung disease with fibrosis is a lesion distinct from fibrotic nonspecific interstitial pneumonia: a proposal. Mod Pathol. 2006 Nov;19(11):1474-9.
  • Ryu JH, Myers JL, Capizzi SA, Douglas WW, Vassallo R, Decker PA. Desquamative interstitial pneumonia and respiratory bronchiolitis-associated interstitial lung disease. Chest. 2005 Jan;127(1):178-84.


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