Pancreaticoduodenal artery pseudoaneurysm

A pseudoaneurysm, also known as a false aneurysm, is a collection of blood that forms between the two outer layers of an artery, the tunica media and the tunica adventitia. It is usually caused by a penetrating injury to the vessel, which then bleeds, but forms a space between the above two layers, rather than exiting the vessel. [Source: Wikipedia ]