Histologic features of lymphoid interstitial pneumonia

Key histologic features

Diffuse interstitial infiltration of involved areas.

Predominantly alveolar septal distribution.

Infiltrates compromised mostly of T and/or B lymphocytes, plasma cells, and macrophages.

Lymphoid hyperplasia (mucosa-associated lymphoid tissue (MALT) hyperplasia) - frequent.

Pertinent negative findings

Lack of tracking along lymphatic routes (bronchovascular bundles, pleura, and interlobular septa), characteristic of lymphomas.

Organizing pneumonia, inconspicuous or absent.

Lack of Dutcher bodies (ie, intranuclear vacuoles containing IgM monoclonal protein seen in Waldenstrom's macroglobulinemia).

Lack of monoclonal light chain staining pattern of plasma cells (polyclonal pattern present).

Lack of extensive pleural involvement or lymph node involvement.

Lack of necrotizing granulomas.

Histologic_features_LIP.htm

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