cirsoid aneurysm cirsoid aneurysm a cirsoid aneurysm, also referred to as an arteriovenous hemangioma is the dilation of a group of blood vessels due to congenital malformations with arterio venous (av) shunting. "cirsoid" means resembling a varix. they are most common on the head or neck. cirsoid aneurysms appear as nodules or papules. histologically, they are composed of both thick- and thin-walled blood vessels.