A 54-year-old male, who was an active smoker of 36 pack-years, presented with pleuritic right-sided chest pain for 5 days. He also suffered from a cough, productive of white sputum for the past month, and had visited a general practitioner who prescribed a course of antibiotics. However, his symptoms persisted. There was no fever, breathlessness, night sweats or constitutional symptoms. He had a past medical history significant for metabolic syndrome and ischemic heart disease. Physical examination was non-contributory. Chest radiograph revealed a 3.6cm spiculated mass lesion in the right lower zone suspicious for malignancy (Fig. 1A). A computed tomography of the chest noted in the right middle lobe a 3.7cm by 2.7cm lung mass with central low attenuation suggestive of necrosis (Fig. 1C). Other findings included mediastinal lymphadenopathy and an adrenal nodule, all of which were highly suspicious for metastatic lung malignancy. Sputum smears for acid-fast bacilli and tuberculosis GeneXPert PCR were unyielding. Patient underwent an endobronchial ultrasound-transbronchial needle aspiration of the subcarinal and right paratracheal nodes, and transbronchial lung biopsy of the right lung mass. The lymph node aspirates demonstrated moderate numbers of lymphocytes with no malignant cells. The transbronchial lung biopsy demonstrated presence of intra-alveolar foamy macrophages with fibrin, suspicious for lipoid pneumonia (Fig. 1E and F). Further history at this point was negative for e-cigarette use, aspiration episodes, traditional medicine use or inhalation of oil-based products. The patient did however, come into contact with paint and industrial glue, both of which contain oil as an additive, during a course of do-it-yourself renovation works which may have resulted in inhalation of these oil-based products. An interval computed tomography of the chest repeated in 3 months from the initial scan, demonstrated near-complete resolution of the mass and decrease in size of the mediastinal nodes (Fig. 1D). The risk factor exposure and improvement in imaging with supportive therapy is highly suggestive of exogenous lipoid pneumonia which was our patient's eventual diagnosis. The patient underwent smoking cessation treatment, and was offered lung cancer screening with year low-dose CT starting at age 55 years to which he agreed. The patient also agreed to start smoking cessation treatment.
Images of lipoid pneumonia. . C. Computed tomography showing a lung mass with central low attenuation and adjacent interstitial thickening and ground glass changes.