Filling of the alveoli with alveolar macrophages; Filling of the alveoli with desquamated epithelial cells; Intra-alveolar accumulation of macrophages
Definition:
Diffuse filling of the distal airsspaces of the lungs, the alveoli, with macrophages. Desquamative interstitial pneumonitis (DIP) is characterized additionally by thickend alveolar septa and by a sparse inflammatory infiltrate that often includes plasma cells and occasional eosinophils. The alveoli are lined by plump cuboidal pneumocytes. Lymphoid aggregates may be present.