Ascending Aorta Hydatid Cyst Presenting as Pseudoaneurysm

Aortic wall with its poor blood supply is a very rare location of Hydatid Cyst (HC) infestation and mediastinal HC is a rare presentation of human hydatidosis. Here, we reported a case of primary mediastinal HC invading the ascending aorta, which initially presented as an aortic aneurysm. The patient underwent open cardiac surgery with cardiopulmonary bypass for resection of the aortic wall HC. During surgical exploration, it was found that the HC had ruptured into blood stream and residual cyst cavity contained a large thrombosis. Thus, the patient underwent ascending aorta replacement and removal of the cyst with thrombotic material. It seems that the signs and symptoms of stroke were related to emboli of cyst contents or thrombotic material into cerebral circulation. Invasion of aortic wall by hydatidosis is an exceedingly rare presentation of HC in the anterior mediastinum that may be wrongly diagnosed as a pseudoaneurysm of ascending aorta. Our study patient had an uneventful recovery and one-year follow-up revealed no recurrence of HC in mediastinum.