Lipoid Pneumonia

Lipoid pneumonia occurs due to the accumulation of lipids within the lung tissue. Autopsy series have reported an incidence of 1.0-2.5% in adult and 8.8% in children. Lipoid pneumonia can be from an exogeneous or an endogenous source. Exogenous lipoid pneumonia is often associated with aspiration of fatty materials, whereas endogenous lipoid pneumonia is associated with an accumulation of lipid-rich debris from destroyed alveolar cells. We describe a 75-year-old man who presented with spiculated lung nodules found incidentally on abdominal CT. Reviews of systems were positive for weight loss, and a history of constipation. A PET/CT revealed spiculated nodules with positive fluorodeoxyglucose (FDG) uptakes. A wedge resection was performed with histopathologic findings consistent with exogenous lipoid pneumonia with granulomatous reaction. We report clinical, radiological, and pathological features of exogenous lipoid pneumonia secondary to chronic aspiration mimicking invasive adenocarcinoma. A high index of suspicion for exogenous lipoid pneumonia should be maintained, especially when evaluating patients with abnormal chest radiographic findings and risk factors for aspirations.