A 41 year old man was admitted for chest pain. A round shaped right hilar mass was seen on the chest x ray (panel A). Seven years previously, he was operated on for a dissection of the ascending aorta with aortic insufficiency. A Medtronic valve graft No. 23 was used to replace the ascending aorta, while the transverse arch was not dissected at the time. Last year, he suffered an episode of sudden chest pain, but did not consult his physician.

ECG gated multislice computed tomography (MSCT) was performed with a volume zoom 4-slice scanner (Siemens, Erlangen, Germany). Full coverage of the thoracic aorta was obtained in a 47 second breath hold, with a 1.25 mm nominal slice thickness. MSCT angiography displayed a dissection of the aortic arch, and a posterior disruption of the distal suture of the prosthetic graft associated with a large impressive bilobular pseudoaneurysm compressing the ascending aorta (panel B). The patient was operated upon and a prosthetic replacement of the aortic arch was performed with reimplantation of the cerebral vessels.

Retrospectively, the chest pain was interpreted as a recurrence of the dissection in the aortic arch leading to a disruption of the distal suture and subsequently to the bilobular pseudoaneurysm.