Surgical Pathology Criteria

Chronic Eosinophilic Pneumonia

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


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

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