Surgical Pathology Criteria

Lymphocytic Interstitial Pneumonitis

Differential Diagnosis

Lymphocytic Interstitial Pneumonitis Nonspecific Interstitial Pneumonia, Cellular Type
Prominent interstitial lymphoid infiltrate Mild to moderate interstitial lymphoid infiltrate
Occasional follicles may be seen Follicles rare
The distinction may not be well defined in some cases


Lymphocytic Interstitial Pneumonitis Extranodal Marginal Zone B Cell Lymphoma
Polymorphous infiltrate Monomorphous infiltate
Predominantly T cells Predominantly B cells
Involvement of pleura and cartilage rare Pleura and cartilage may be involved
Dutcher bodies not seen Dutcher bodies may be seen
Polyclonal Monoclonal


Lymphocytic Interstitial Pneumonitis Hypersensitivity Pneumonitis
Diffuse involvement of alveolar septa Predominantly peribronochiolar
Marked infiltrate Patchy, less dense infiltrate
No BOOP-like foci BOOP-like foci common
Both may have loose granulomas and develop honeycomb change


Lymphocytic Interstitial Pneumonitis Follicular Bronchiolitis
Predominantly T cell infiltrate Prominent B cell follicles
Predominantly interalveolar Predominantly peribronchiolar
Occasional caess will show features of both


Lymphocytic Interstitial Pneumonitis Nodular Lymphoid Hyperplasia
Diffuse involvement of alveolar septa Discrete nodule(s)
Germinal centers, if present, are a minor component Prominent germinal center hyperplasia

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