Exogenous lipoid pneumonia following ingestion of liquid paraffin

An asymptomatic patient with exogenous lipoid pneumonia (ELP) due to silent aspiration of liquid paraffin ingested as a lubricant was diagnosed by bronchoalveolar lavage (BAL). BAL fluid separated into oily upper phase and lower aqueous phase spontaneously. Microscopic analysis of BAL cells revealed the presence of lipid-laden alveolar macrophages. Classic histochemical staining and electron microscope examination indicated that neutral lipid was dominant but phospholipid was also present in the lipid-laden macrophages. Together with the history of ingestion of liquid paraffin, we identified that the ingested liquid paraffin was the origin of the neutral lipid in the lipid-laden macrophages observed in the BAL fluid.