Impersonation of a ruptured thoracic aneurysm by a transdiaphragmatic pancreatic cyst

Pancreatic cysts can, in rare cases, expand into the posterior mediastinum and may require surgical resection. We present the case of a patient with a thoracic aneurysm, in whom the mediastinal involvement of a chronic pancreatic cyst masqueraded as a ruptured aneurysm. Surgery was undertaken: first, the initial resection and drainage of the thoracic portion of the pseudocyst, and second, a thorough cleansing of the entire cyst through median laparotomy 15 days later.