Positron Emission Tomography-Positive Squalene-induced Lipoid Pneumonia Confirmed by Gas Chromatography–Mass Spectrometry of Bronchoalveolar Lavage Fluid

ABSTRACT Squalene is a type of oil obtained from shark liver. We describe a 76-year-old man diagnosed with chronic exogenous lipoid pneumonia due to squalene. A chest CT scan revealed pulmonary consolidation with ground-glass opacities in the right upper lobe. Positron emission tomography (PET) revealed significant uptake of 2-deoxy-2- 18 F-fluoro-d-glucose (FDG) and 3′-deoxy-3′- 18 F-fluorothymidine (FLT). Bronchoalveolar lavage (BAL) fluid contained many lipid-laden macrophages, and a transbronchial lung biopsy specimen showed clusters of foamy macrophages in alveolar spaces and granulomatous lesions. In addition, the presence of squalene in the BAL fluid was confirmed by gas chromatography–mass spectrometry, leading to a diagnosis of squalene-induced lipoid pneumonia. To the best of our knowledge, this is the first report of squalene-induced lipoid pneumonia in which squalene itself was successfully detected. This case also suggests the possibility that lipoid pneumonia shows significant uptake in FDG-PET and FLT-PET.