The most common sources for
lipids producing radiographic or clinical evidence of disease in the lungs are endogenous
lipids and inhaled (exogenous)
mineral oil.
Endogenous lipoid pneumonia arises when lung tissue breaks down distal to an obstructed airway leading to the release of
cholesterol and other
lipids, producing airspace disease.
Exogenous lipoid pneumonia occurs most frequently in the elderly following habitual
mineral oil use. Many patients have no specific predisposing cause for aspiration of the ingested
mineral oils. Symptoms, found in only half of the patients reviewed, include
chronic cough and sputum production. Radiographically, the lesions are usually ill-defined radiopacities that mimic
carcinoma of the lung. The inhaled
mineral oil incites a
foreign-body reaction, producing a
granuloma with multinucleated foreign-body giant cells and
fibrosis surrounding lipid droplets. Diagnostic strategies such as sputum examination for
lipids and transthoracic needle aspiration are discussed. These procedures may help to avoid
thoracotomy in elderly, often debilitated patients with
lipoid pneumonia.