Silent threat: A case report of acute fulminant exogenous lipoid pneumonia leading to severe ARDS

Exogenous lipoid pneumonia (ELP) is a rare pulmonary disorder resulting from the aspiration or inhalation of exogenous lipid substances. While most documented cases follow an indolent, chronic course and are associated with favorable outcomes, fulminant postoperative ELP remains exceedingly uncommon—often presenting with rapid respiratory decompensation that may clinically and radiologically mimic severe community-acquired pneumonia or acute respiratory distress syndrome (ARDS). We report a 61-year-old man with occult fulminant postoperative ELP after repeated oral liquid paraffin use for bowel obstruction caused by a large rectal neoplasm. No definite aspiration event was witnessed. After emergency diverting ileostomy, he developed rapidly progressive refractory hypoxemia with bilateral ground-glass opacities and consolidations on chest CT. BALF pathogen testing was largely negative, although a positive galactomannan result meant that fungal coinfection could not be fully excluded. Oil Red O staining demonstrated lipid-laden macrophages, supporting the diagnosis of ELP. Despite invasive mechanical ventilation, prone positioning, segmented alveolar lavage, systemic corticosteroids, adjunctive IVIG, respiratory failure progressed. The patient died three days after discharge against medical advice, most likely from progressive respiratory failure. This case highlights a rare and fulminant form of postoperative exogenous lipoid pneumonia following liquid paraffin exposure for bowel obstruction. Early recognition is important because ELP may coexist with infection and can progress rapidly despite intensive supportive care.