[Lipoid pneumonia - an underestimated syndrome]

Lipoid pneumonia, first described by Laughlen 1925 may be classified as endogenous or exogenous. The endogenous form is seen when fat is deposited into the lung tissue. It is usually associated with proximal obstructive lesions, necrotic tissue after radio- or chemotherapy, with lipid storage disease or hyperlipidemia . Exogenous lipoid pneumonia results from inhaling or aspirating animal, vegetable or mineral oil. There are usually some underlying neurological defects or esophageal abnormalities. Patients may present with cough, sputum, hemoptysis and chest pain or may be asymptomatic. There is no classic chest film appearance: it may appear as diffuse airspace infiltration or localized consolidation simulating tumour. Computed tomography is diagnostically helpful and shows hypodense areas measuring from -100 to - 30 Hounsfield units. Bronchoscopic biopsies are mandatory for histological confirmation of the diagnosis. Treatment of exogenous lipoid pneumonia has always been conservative by discontinuing the use of oil, correction of underlying defects that may favor aspiration and treatment of intercurrent pneumonia. Other measures, for example corticosteroid therapy, are of uncertain benefit. Complications of lipoid pneumonia that worsen prognosis are recurrent bacterial pneumonias including nontuberculous mycobacteria or aspergillus, or lung cancer that has developed in areas of pre-existing exogenous lipoid pneumonia.