[en] A 31 year-old male was admitted because of abnormal chest X-ray findings simulating atelectasis of the right middle and lower lobe. Bronchogram showed that the middle and lower lobe bronchi were displaced by a mass on the diaphragm. Computed tomography (CT) demonstrated that the mass consisted of low density material, suggesting a lipoma originating from the anterior mediastinum. Thoracotomy revealed that it was an entirely encapsulated, yellowish and pliable tumor weighed 700 gm. Histologically, the tumor consisted mostly of mature adipose tissue, scattered with small islands of thymic tissue, and was diagnosed as thymolipoma. (author)