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Acute Lung Injury w/ Eosinophils

There are 3 required histologic features to diagnose an acute eosinophilic pneumonia pattern of injury:

  1. Numerous eosinophils (unless the pateint has been treated with steroids)

  2. Fibrin and other features of acute lung injury (with eosinophils)

  3. Markedly reactive appearing pneumocytes

    If your biopsy has all three of these findings, you can diagnose acute eosinophilic pneumonia (AEP).  However, AEP is a nonspecifc reaction pattern and the etiologic differential diagnosis includes infection, adverse drug reaction, changes in smoking habits, and as an idiopathic disease. Fortunately, with the exception of infection, this reaction pattern is markedly responsive to HIGH dose steroids.

Acute eosinophilic pneumonia

Fibrin in Air Spaces

AEP 1.jpg

Prominent Eosinophils

Reactive Type II Pneumocytes

Sample Signout

If no additional specific histologic features are identified, consider the following approach to signing the case out:

Acute (and organizing) lung injury with eosinophils (see comment).

Comment:  The biopsy shows acute and organizing lung injury with abundant eosinophils.  The differential diagnosis includes acute eosinophilic pneumonia (idiopathic), infection, adverse drug reaction, and changes in smoking habits.  Correlation with final culture studies to exclude infection is suggested.  If infection is excluded, this pattern of injury is typically responsive to high dose steroids.