Masson's pseudoangiosarcoma, alias intravascular papillary endothelial hyperplasia, in dissecting aortic aneurysm caused by cystic medionecrosis.

This report describes a 25-year-old man who died due to extensive cystic medionecrosis of the aortic wall complicated by both an acute and an ancient dissection. The very unusual finding of an intravascular papillary endothelial hyperplasia, also known as Masson's pseudoangiosarcoma, in the dissected wall is reported given its resemblance to a hemangiosarcoma.