Which statement about abdominal aortic aneurysms is true?

Which statement about abdominal aortic aneurysms is true?

• A. They are always fusiform
• B. They never contain thrombus
• C. They originate in the intima only
• D. They can be saccular or fusiform

Answer: (D)

Abdominal aortic aneurysms can take different shapes, reflecting how the wall weakness distributes along the aorta. A true aneurysm involves dilation of all three layers of the vessel wall and can be either fusiform (a symmetric, belt-like widening) or saccular (a localized, pouch-like outpouching). Because of this variability, they are not limited to one form. Many AAAs also harbor a mural thrombus, especially when the lumen is large and flow is sluggish, so option claiming no thrombus is present isn’t accurate. Also, aneurysms don’t originate merely in the intima; a true aneurysm entails involvement of the media and adventitia as well. So the correct statement is that they can be saccular or fusiform.

Abdominal aortic aneurysms can take different shapes, reflecting how the wall weakness distributes along the aorta. A true aneurysm involves dilation of all three layers of the vessel wall and can be either fusiform (a symmetric, belt-like widening) or saccular (a localized, pouch-like outpouching). Because of this variability, they are not limited to one form. Many AAAs also harbor a mural thrombus, especially when the lumen is large and flow is sluggish, so option claiming no thrombus is present isn’t accurate. Also, aneurysms don’t originate merely in the intima; a true aneurysm entails involvement of the media and adventitia as well. So the correct statement is that they can be saccular or fusiform.