An unusual case of leiomyoma of the middle third of the esophagus compressing the left atrium is reported. The patient was a 35-year-old man with a clinical picture mimicking pericarditis. 2-D echocardiography revealed a mediastinal mass. Leiomyoma of the esophagus was suspected on the basis of CT scan of the chest, MR study and esophagogram. The diagnosis was confirmed at operation and by histological examination.