Lipoid Pneumonia.

Lipoid pneumonia is an uncommon disorder characterized by intra-alveolar lipid accumulation and classified as exogenous or endogenous. Exogenous forms most commonly result from aspiration of oil-based substances, whereas endogenous forms are associated with airway obstruction, malignancy, inflammatory disorders, and impaired macrophage function. Imaging manifestations are varied and frequently misleading, ranging from ground-glass opacities and consolidation to crazy-paving, nodules, and mass-like lesions that may closely mimic malignancy, infection, or other alveolar filling disorders. Although low-attenuation, fat-containing pulmonary opacities are characteristic, they are absent in many patients, making diagnosis challenging and often requiring clinicoradiologic-pathologic correlation. Bronchoalveolar lavage and histopathology may provide supportive evidence but lack complete specificity. Management focuses on eliminating the inciting exposure, reducing future aspiration risk, providing supportive care, and treating superimposed infection, while corticosteroids and therapeutic lavage have been used in selected severe cases.