[Analysis of 12 cases of exogenous lipoid pneumonia confirmed by pathology]

Objective: To study the etiological, clinical, radiological, diagnostic, therapeutic, and prognostic manifestations of exogenous lipoid pneumonia (ELP), and therefore to improve the diagnosis and treatment of this disease. Methods: The clinical data of 12 cases of ELP confirmed by pathology were retrospectively analyzed. Results: The patients consisted of 9 males and 3 females, with an average age of 73.8 years (range, 44 to 100 years). The underlying diseases were variable, including diseases affecting the general condition (multiple organ failure, chronic heart and renal insufficiency, pemphigoid, etc) and conditions with increased risk of aspiration (sequelae of cerebrovascular disease, Alzheimer's disease, advanced stage of nasopharyngeal carcinoma, paralytic ileus, etc). The 12 cases were all caused by Inhalation of mineral oil. Common symptoms included cough, sputum production and dyspnea. ELP had no special physical signs. Inflammation indexes, such as white blood cell, neutrophil percentage, ESR, C reactive protein, procalcitonin, D-Dimer, and blood lipid levels were usually normal. Radiological features of ELP mainly included consolidation, mass or nodules, with a little ground-glass opacity. Some patients had ventilation and/or diffusion dysfunction. The diagnostic methods included CT-guided percutaneous lung biopsy, thoracoscopy, thoracotomy or autopsy. Histopathological findings showed accumulation of large foamy macrophages in the alveolar spaces, with a few lipid deposition and polykaryocytes. The main treatment of ELP was cessation of lipid material contact. One case died of ELP, 6 died of other coexisting diseases, and the rest 6 improved with treatment and were discharged. The survival patients were all stable during a follow-up of 2-4.5 years. Conclusions: ELP was rare and its clinical manifestation was atypical. Its radiological manifestations were indistinguishable from pneumonia, lung cancer, interstitial lung diseases, etc. Pathological examination was the gold standard for diagnosis, and the preferred means of sampling was bronchoscopy. In cases whose diagnosis could not be confirmed by BALF, CT-guided percutaneous lung biopsy might be considered. The most important treatment is cessation of lipid material contact. The prognosis is good.