Objective: The purpose of this study was to describe six cases of migrating azygos vein and to explain the etiologic factors that contribute to the migration. Six patients with migrating azygos vein were studied by MDCT before and after migration. Five patients had right pneumothorax. All patients had repeated episodes of cough, vomiting, and a short mesoazygos.
Conclusion: Pneumothorax, increased intrathoracic pressure, and a short mesoazygos, in combination or alone, are the main factors in azygos vein migration.