Desquamative interstitial pneumonia

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Desquamative interstitial pneumonia
Diagnosis in short

Desquamative interstitial pneumonia. H&E stain. (WC/Nephron)

LM abundant brown pigmented airspace macrophages (smoker's macrophages), architecture preserved ("linear fibrosis")
LM DDx amiodarone toxicity, fibrotic NSIP, RBILD
Site lung - see diffuse lung diseases

Associated Dx +/-smoking
Prevalence rare
Radiology ground glass airspaces changes - usu. all lobes but peripheral predominant and in lower lobe predominant
Treatment stop smoking/remove insult

Desquamative interstitial pneumonia, abbreviated DIP, is a diffuse lung disease that is strongly associated with smoking.

The term desquamative interstitial pneumonia is a misnomer. The airspace cells that characterize the condition were once thought to represent desquamated epithelial cells, but they are now know to represent macrophages.[1]

General

  • Rare.[2]
  • Strong association with smoking.[3][4]
    • Thought to be advanced RBILD.
  • May be seen in non-smokers (up to ~40% of cases) due to occupational exposures, drugs, viral illnesses and autoimmune diseases.[5]

Diagnosis:

  • Requires - surgical biopsy.[5]

Treatment:

  • Stop smoking/remove or manage underlying cause.

Gross/Radiology

Features:[6]

  • Ground glass (airspace changes).
    • Usually peripheral predominant (~60% of cases) and lower lobe predominant (~70-75% of cases).
    • Typically all lobes are involved - though upper lobe spared in ~20% of cases.
  • Fibrotic (radiologic) changes ~50% of cases.

Microscopic

Features:[2]

  • Abundant airspace macrophages - usually with brown pigment (so called smoker's macrophages) - key feature.
  • Interstitial inflammation or interstitial fibrosis with a preserved architecture - so called "linear fibrosis".

Notes:

  • Some fields of view may be indistinguishable from RBILD.

DDx:

Images

www

Stains

  • Macrophages PAS +ve.

See also

References

  1. Attili, AK.; Kazerooni, EA.; Gross, BH.; Flaherty, KR.; Myers, JL.; Martinez, FJ.. "Smoking-related interstitial lung disease: radiologic-clinical-pathologic correlation.". Radiographics 28 (5): 1383-96; discussion 1396-8. doi:10.1148/rg.285075223. PMID 18794314. http://pubs.rsna.org/doi/full/10.1148/rg.285075223.
  2. 2.0 2.1 Tazelaar, HD.; Wright, JL.; Churg, A. (Mar 2011). "Desquamative interstitial pneumonia.". Histopathology 58 (4): 509-16. doi:10.1111/j.1365-2559.2010.03649.x. PMID 20854463.
  3. Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 93. ISBN 978-0781765275.
  4. Margaritopoulos, GA.; Vasarmidi, E.; Jacob, J.; Wells, AU.; Antoniou, KM. (Sep 2015). "Smoking and interstitial lung diseases.". Eur Respir Rev 24 (137): 428-35. doi:10.1183/16000617.0050-2015. PMID 26324804.
  5. 5.0 5.1 Godbert, B.; Wissler, MP.; Vignaud, JM. (Jun 2013). "Desquamative interstitial pneumonia: an analytic review with an emphasis on aetiology.". Eur Respir Rev 22 (128): 117-23. doi:10.1183/09059180.00005812. PMID 23728865.
  6. Hartman, TE.; Primack, SL.; Swensen, SJ.; Hansell, D.; McGuinness, G.; Müller, NL. (Jun 1993). "Desquamative interstitial pneumonia: thin-section CT findings in 22 patients.". Radiology 187 (3): 787-90. doi:10.1148/radiology.187.3.8497631. PMID 8497631.