Esophageal invasion by lung cancer: CT diagnosis.

Esophageal wall invasion by primary lung carcinoma is an uncommon occurrence. When CT demonstrates a large primary parenchymal lung lesion that appears to cross the midline in the posterior mediastinum, dilute oral barium should be given during the CT examination to demonstrate the location of the esophagus. An esophagus involved by lung carcinoma may show contralateral displacement or partial obstruction. Furthermore, a malignant fistula between esophagus and trachea or lung may also be discovered.