Lipoid pneumonia: an uncommon entity.

Lipoid pneumonia is a rare form of pneumonia caused by inhalation or aspiration of fat-containing substances like petroleum jelly, mineral oils, certain laxatives, etc. It usually presents as an insidious onset, chronic respiratory illness simulating interstitial lung diseases. Rarely, it may present as an acute respiratory illness, especially when the exposure to fatty substance(s) is massive. Radiological findings are diverse and can mimic many other diseases including carcinoma, acute or chronic pneumonia, ARDS, or a localized granuloma. Pathologically it is a chronic foreign body reaction characterized by lipid-laden macrophages. Diagnosis of this disease is often missed as it is usually not considered in the differential diagnoses of community-acquired pneumonia; it requires a high degree of suspicion. In suspected cases, diagnosis may be confirmed by demonstrating the presence of lipid-laden macrophages in sputum, bronchoalveolar lavage fluid, or fine needle aspiration cytology/biopsy from the lung lesion. Treatment of this illness is poorly defined and constitutes supportive therapy, repeated bronchoalveolar lavage, and corticosteroids.