Stanford School of Medicine

Surgical Pathology Criteria

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Desquamative Interstitial Pneumonia


  • Diffuse expansion and filling of alveoli by macrophages

Diagnostic Criteria

  • Clinical
    • Nearly all affected patients are smokers
      • Adults, average age 30-60
    • Generally subacute dyspnea, cough
    • Good response to steroids and smoking cessation
      • 70% 10 year survival
  • High resolution computed tomography (HRCT)
    • Bilateral ground glass opacities
      • Lower lung fields
      • May be peripheral and patchy
  • Histopathologic features
    • Diffuse, uniform expansion and filling of alveoli and distal airways by macrophages
      • Macrophages contain finely granular golden brown pigment
        • Iron positive
        • Termed "smokers macrophages"
    • Mild to moderate fibrotic thickening of alveolar septa
      • Architecture is preserved
      • No scarring or honeycomb change
      • Fibroblastic foci rare
    • Mild interstitial infiltrate of plasma cells and lymphocytes
      • Lymphoid follicles frequently present but scattered
      • Eosinophils frequently present but sparse, neutrophils absent
    • Alveoli lined by reactive alveolar lining cells
    • Occurring in smokers' lungs, other clinicopathologic disorders such as chronic bronchitis and emphysema are frequently present
    • The following features should not be seen
        • Fibroblastic foci or organizing pneumonia
        • Honeycomb change
        • Restriction to bronchiolocentric distribution
        • Granulomas or foreign body giant cells
        • Foreign material other than anthracotic pigment
          • No asbestos
        • More than occasional itra-alveolar eosinophils
        • Evidence of infection
  • May form a spectrum with respiratory bronchiolitis associated interstitial lung disease
    • Patchy (RBAILD) vs. diffuse (DIP) airspace involvement by macrophages
  • Similar infiltrates may be seen adjacent to tumors and scars

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; 8/13/11, 12/29/12

Differential Diagnosis

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


Langerhans Cell Histiocytosis Desquamative Interstitial Pneumonia
Intra-alveolar macrophages only focally present Diffuse intra-alveolar macrophages
Temporal heterogeneity Temporally uniform
Focal or multifocal disease Diffuse disease
Numerous eosinophils Occasional eosinophils
Cystic change frequent No cystic change
Produces stellate scars Lacks scarring
Histiocytes with folded nuclei Histiocytes with round nuclei
Langerhans cells positive for CD1a and langerin Macrophages CD1a and langerin negative


Giant Cell Interstitial Pneumonia Desquamative Interstitial Pneumonia
Centrilobular distribution Diffuse intra-alveolar macrophages
Numerous multinodular giant cells Giant cells not present
Heavy metal may be identified No heavy metals


Usual Interstitial Pneumonia Desquamative Interstitial Pneumonia
Intra-alveolar macrophages only focally present Diffuse intra-alveolar macrophages
Temporal heterogeneity Temporally uniform
Architecture destroyed, honeycomb change prominent Architecture preserved, honeycomb change uncommon
Fibroblastic foci common Fibroblastic foci absent
Interstitial fibrosis marked Interstitial fibrosis mild to moderate
Interstitial fibrosis variably distributed Interstitial fibrosis tends to be more uniform


Desquamative Interstitial Pneumonia Acute Eosinophilic Pneumonia
Subacute onset Acute, fulminant onset
Eosinophils infrequent Prominent eosinophils in lavage and biopsy specimens
Following steroid treatment, eosinophils may be harder to identify


Post-obstructive Pneumonia Desquamative Interstitial Pneumonia
Foamy macrophages Finely granular macrophages
No pigment in macrophages (unless a smoker) Pigment in macrophages
No interstitial pneumonitis Interstitial pneumonitis present (but mild)
Localized Generalized


  • Infection must always be ruled out
    • Especially important in immunosuppressed patients
    • Atypical mycobacteria may simulate this pattern
  • Asbestosis and drug reactions should be ruled out clinically and by searching for asbestos bodies
  • Amiodarone may produce non-pigmented coarsley foamy macrophages
    • Usually associated with organizing pneumonia or acute interstitial pneumonia

Classification / Lists

Smoking Related Lung Diseases

Idiopathic Interstitial Lung Diseases

Other Diffuse Parenchymal Lung Diseases



  • Travis WD, Colby TV, Koss MN, Rosado-de-Christenson ML, Müller NL, King TE Jr.  Non-neoplastic Disorders of the Lower Respiratory Tract, AFIP Atlas of Nontumor Pathology, First Series, Fascicle 2, 2002.
  • 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.
  • Visscher DW, Myers JL. Histologic spectrum of idiopathic interstitial pneumonias. Proc Am Thorac Soc. 2006 Jun;3(4):322-9.
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  • Tazelaar HD, Wright JL, Churg A. Desquamative interstitial pneumonia. Histopathology. 2011 Mar;58(4):509-16.
  • Craig PJ, Wells AU, Doffman S, Rassl D, Colby TV, Hansell DM, Du Bois RM, Nicholson AG. Desquamative interstitial pneumonia, respiratory bronchiolitis and their relationship to smoking. Histopathology. 2004 Sep;45(3):275-82.
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