[A case of progressive saccular aneurysm caused by localized dissection of descending aorta].

A fifty-three-year-old man was admitted because of chest pain. CT scan showed the localized dissection of the descending aorta which was partially thrombosed. The patient was followed by controlling of essential hypertension. He, however, complained of the second attack of chest pain after a year and 5 months. CT scan showed the increased dilatation of the false lumen as compared to that of previous examination. MR angiogram showed a saccular aneurysm localized in the middle portion of the descending aorta. An operation was performed through posterolateral thoracotomy in the 4th intercostal space with the aid of normothermic femoro-femoral bypass circulation. The aneurysm was located at the level of 5th thoracic vertebra with the size of 70 mm in length and 45 mm in diameter. Entry was observed in the posterior wall of the aorta, and the terminal end of the false lumen was occluded with the organized thrombus. The aneurysm was successfully replaced with a prosthetic graft. To the extent of our knowledge, only limited surgical cases of saccular aneurysm caused by localized dissection of the middle portion of the descending aorta have been reported.