Background. We report two cases of acute eosinophilic pneumonia (AEP) possibly induced by menthol cigarette smoking. Case 1. A 16-year-old man was admitted to our hospital complaining of fever and dyspnea. Chest radiograph and CT revealed patchy ground-glass opacities in the right lung field with thickened interlobular septa and bilateral pleural effusions. Laboratory data showed leukocytosis with neutrophilia and hypoxemia. Case 2. A 18-year-old man was admitted to our hospital complaining of fever and dyspnea. Chest radiograph and CT revealed patchy ground-glass opacities in the both lung fields with thickened interlobular septa and bilateral pleural effusions. The bronchoalveolar lavage fluid (BALF) of both cases revealed an increase in eosinophil. Both of cases were diagnosed as AEP induced by menthol cigarette smoking. Corticosteroid therapy immediately improved their symptoms, ground-glass opacities and pleural effusions. Conclusions. In these 2 cases, menthol cigarette induced AEP but non-menthol cigarette did not. These two cases suggested that menthol cigarette smoking may induce AEP.
