Lipoid pneumonia Endogenous lipoid pneumonia 2020-12-16T11:45:51Z A type of lipoid pneumonia in which the source of the lipids is the body itself. When an airway is obstructed, it is often the case that distal to the obstruction, lipid-laden macrophages and giant cells fill the lumen of the disconnected airspace. Endogenous lipoid pneumonia is a histopathologic diagnosis made on the basis of the characteristic appearance of the obstructive pneumonitis. Macroscopically, there is parenchymal consolidation that has a characteristic yellowish discoloration due to the accumulation of lipid in the alveoli. Histologically, there is an accumulation of lipid-filled macrophages and eosinophilic proteinaceous material derived from degenerating cells, including surfactant from type II pneumocytes, in the alveoli distal to the bronchial obstruction.