Lymphoid interstitial pneumoniaRadlex concept

Pathology.—LIP is a rare disease characterized by diffuse pulmonary lymphoid proliferation with predominant interstitial involvement. It is included in the spectrum of interstitial pneumonias and is distinct from diffuse lymphomas of the lung. Features include diffuse hyperplasia of bronchus-associated lymphoid tissue and diffuse polyclonal lymphoid cell infiltrates surrounding the airways and expanding the lung interstitium. LIP is usually associated with autoimmune diseases or human immunodeficiency virus infection (5,81). CT scans.—Ground-glass opacity is the dominant abnormality, and thin-walled perivascular cysts may be present (Fig 37). Lung nodules, a reticular pattern, interlobular septal and bronchovascular thickening, and widespread consolidation may also occur (82,83). [Fleischner Society]