Stanford School of Medicine

Surgical Pathology Criteria

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Chronic Eosinophilic Pneumonia


  • Chronic respiratory disorder associated with pulmonary eosinophil infiltration

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Diagnostic Criteria


  • Chronic dyspnea, cough
    • Respiratory failure uncommon
    • Weight loss, fever, night sweats common
    • May have history of asthma, atopy
  • Mean age 45
  • Rapid response to steroids
    • 50% relapse


  • Bilateral diffuse opacities with peripheral accentuation
    • "Photographic negative of pulmonary edema" classic but seen in <50%


  • Hypereosinophilia must be demonstrated in the blood or lung to make the diagnosis
    • Blood eosinophils usually >1000/mm3
      • Steroid treament may dramatically reduce eosinophilia
    • Bronchoalveolar lavage (BAL) fluid shows eosinophils > lymphocytes
      • Usually >40%
    • Tissue biopsy shows prominent eosinophilic infiltrate
      • Biopsy is not usually necessary for diagnosis but may help rule out infection
      • Intra-alveolar and usually interstitial
        • May have eosinophilic microabscesses with central necrosis
        • May invade vessel walls but no necrosis or granulomatous vasculitis
      • 5-25% eosinophils is consistent with diagnosis, >25% is suggestive
        • Eosinophils are rare in normal lung (<2%)
      • Sarcoid like granulomas without necrosis may be present
      • Organizing pneumonia may be present
  • Known causes must be ruled out
    • Drugs including antibiotics, non-steroidal anti-inflammatory, anti-hypertensive, heroin, cocaine
    • Organisms including fungi and parasites
      • Allergic bronchopulmonary aspergillosis

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

Simple Eosinophilic Pneumonia Acute Eosinophilic Pneumonia Chronic Eosinophilic Pneumonia
Asymptomatic to mild symptoms Fulminant respiratory insufficiency Chronic dyspnea, cough
Blood eosinophils mildly elevated Blood eosinophils normal to mildly elevated Blood eosinophils >1000/mm3
No direct treatment required Steroid responsive, no relapses Steroid responsive, 50% relapse


Known causes of eosinophilic pneumonia must be ruled out

  • Drugs
    • Check history
    • Skin rash suggestive
  • Organisms
    • Check travel history
    • Check stool ova and parasites
    • Check serology for fungi and parasites
    • Culture and stain lavage and biopsy specimens
    • Allergic bronchopulmonary aspergillosis
      • Bronchiolocentric
      • May have necrotizing granulomatous bronchiolitis
      • Mucus plugs common
      • Culture, serology, biopsy identification


Churg-Strauss Syndrome Acute Eosinophilic Pneumonia
Heart, kidneys, skin, gi, nervous system, other organs involved Restricted to lung

pANCA and anti-myeloperoxidase positive in 50%

pANCA and anti-myeloperoxidase negative
Granulomatous vasculitis on lung biopsy No granulomatous vasculitis


Idiopathic Hypereosinophilic Syndrome Chronic Eosinophilic Pneumonia
Blood eosinophilia >1500/mm3 for 6 months Blood eosinophilia >1000/mm3
Heart, other organs involved Restricted to lung
No asthma Asthma may be seen


Langerhans Cell Histiocytosis Chronic Eosinophilic Pneumonia
Predominantly interstitial process, intra-alveolar macrophages only focally present Predominantly intra-alveolar process
Composed of Langerhans cells with variable numbers of eosinophils Prominent eosinophils, no Langerhans cells
Produces stellate scars Lacks scarring
Histiocytes with folded nuclei Histiocytes with round nuclei
S100, CD1a, langerin positive S100, CD1a, langerin negative

Classification / Lists

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.
  • Tazelaar HD, Linz LJ, Colby TV, Myers JL, Limper AH. Acute eosinophilic pneumonia: histopathologic findings in nine patients. Am J Respir Crit Care Med. 1997 Jan;155(1):296-302.
  • Pope-Harman AL, Davis WB, Allen ED, Christoforidis AJ, Allen JN. Acute eosinophilic pneumonia. A summary of 15 cases and review of the literature. Medicine (Baltimore). 1996 Nov;75(6):334-42.
  • Jederlinic PJ, Sicilian L, Gaensler EA. Chronic eosinophilic pneumonia. A report of 19 cases and a review of the literature. Medicine (Baltimore). 1988 May;67(3):154-62.
  • Marchand E, Cordier JF. Idiopathic chronic eosinophilic pneumonia. Orphanet J Rare Dis. 2006 Apr 6;1:11..
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