Lipoid pneumonia showing multiple pulmonary nodules and reversed halo sign

SummaryWe describe a 50-year-old man diagnosed with chronic exogenous lipoid pneumonia due to inhalation of paint spray. CT scan revealed multiple pulmonary nodules in both lungs. Resected specimens showed clusters of foamy macrophages in alveolar spaces, suggesting lipoid pneumonia. Long time inhalation of a small amount of paint oil may lead to lipoid pneumonia showing rare patterns such as multiple pulmonary nodules without surrounding parenchymal abnormal shadows. Five months later, some nodules increased still more in size, and some revealed reversed halo sign on CT. This case also suggests that reversed halo sign can be shown in lipoid pneumonia.