Surgical Pathology Criteria

Acute Interstitial Pneumonia - Diffuse Alveolar Damage

Differential Diagnosis

Usual Interstitial Pneumonia Acute Interstitial Pneumonia
Temporal heterogeneity Temporally uniform
Honeycomb change prominent Honeycomb change only in late stage
Patchy distribution with subpleural accentuation Diffuse, uniform throughout
Hyaline membranes not seen Hyaline membranes prominent in early stage

 

Nonspecific Interstitial Pneumonia Acute Interstitial Pneumonia
Predominantly interstitial Prominent intra-alveolar component
No hyaline membranes Hyaline membranes prominent in early stage
Intra-alveolar organization rare and focal Prominent intra-alveolar organization in intermediate stage
Honeycomb change rare Diffuse honeycomb change may be seen in late stage
Insidious onset, chronic disease Acute onset

 

Cryptogenic Organizing Pneumonia Acute Interstitial Pneumonia
Patchy distribution Diffuse
No hyaline membranes Hyaline membranes prominent in early stage and fragments in organizing phase
No collagen deposition, architecture preserved Diffuse honeycomb change may be seen in late stage

 

Acute Interstitial Pneumonia / Diffuse Alveolar Damage Acute Eosinophilic Pneumonia
Eosinophils infrequent Prominent eosinophils in lavage and biopsy specimens
Not steroid responsive, poor prognosis Steroid responsive, no relapses
Diffuse alveolar damage pattern may be seen in acute eosinophilic pneumonia

 

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