A Rare Cause of Pneumonia-Exogenous Lipoid Pneumonia

Exogenous lipoid pneumonia (ELP) is a rare respiratory disorder. We are describing its clinical manifestations, diagnosis, and treatment.

Patients with ELP were identified by reviewing the hospital medical records between January 2020 and December 2024. Clinical characteristics, disease progression, examination results, treatments, and outcomes were presented.

Three male patients and one female patient were identified (59-78 years old), all with a history of oil exposure. They presented with fever, cough, and expectoration. Laboratory tests revealed elevated neutrophil counts, C-reactive protein, and interleukin-6, as well as decreased lymphocyte counts and normal procalcitonin levels. All patients underwent bronchoscopy. Pathological examination revealed neutrophil infiltration, fat droplets, and lipid-laden macrophages. One patient had a positive chylous test in bronchoalveolar lavage fluid. In the chest images, four patients had large areas of consolidation; two patients had exudation and heterogeneous density within the consolidation areas, which were identified as fat attenuation zones on the mediastinal window. Bronchoscopic alveolar lavage and glucocorticoids were the key treatments. Three patients developed respiratory distress. Two of these patients required mechanical ventilation and circulatory support. One patient with esophageal cancer died, while the other patients successfully recovered after veno-venous extracorporeal membrane oxygenation treatment.

ELP is rare. Affected patients can rapidly progress into respiratory failure. Pulmonary imaging with heterogeneous fat attenuation areas in the mediastinal window can suggest its diagnosis. Identification of lipid droplets and lipid-laden macrophages or having a positive chylous test in bronchoalveolar lavage fluid can facilitate its early and rapid diagnosis. ELP treatment requires a comprehensive approach, including bronchoscopic lavage, glucocorticoids, and respiratory and circulatory support.