Coexistence of cystic medial necrosis and segmental arterial mediolysis in a patient with aneurysms of the abdominal aorta and the iliac artery.

Segmental arterial mediolysis is an unusual arterial lesion for which pathogenesis has remained controversial. We report on a 47-year-old Japanese woman who underwent surgery for an abdominal aortic aneurysm that was 10.5 cm in diameter and contiguous with a left common iliac aneurysm that was 2.3 cm in diameter; the aneurysms were considered to have progressed rapidly in size. Pathologic examinations of the respective aneurysms showed cystic medial necrosis in the aortic and segmental arterial mediolysis in the iliac aneurysm. Coexistence of these two pathologic findings indicates that there may be a strong relation between these two disease entities.