《Slide 50.》Dissecting aneurysm , Blood vessel

A. Brief Descriptions：

1. An aneurysm is a localized abnormal dilation of a blood vessel.

2. Dissection of blood vessel along the laminar planes of arterial media with the formation of a blood-filled channel.

3. Cystic medial degeneration è weakened arterial wall è hemodynamic factors (H/T) è intimal tear è dissecting aneurysm è reenter the lumen distally to create a second channel, or rupture through the vessel wall.

B. Gross Findings：

1. Dissection of blood vessel along the laminar planes of arterial media with the formation of a blood-filled channel.

C. Micro Findings：

1. Dissection between middle and outer thirds of tunica media with the formation of two lumens (Medial splitting by hemorrhage；usually associated with elastic fragmentation and fibrosis).

   • true lumen :endotheial-lining wall, smooth.

   • false lumen: RBC-coating wall, irregular.

D. Others:

   略.

E. Reference：

1. Robbins Pathologic Basis of Disease, 6^th ed.  P.525.

 

 

 

【 Fig. 50-1 (LP)】Dissecting aorta with two lumens: true lumen in the right, while false lumen in the left; note nerve ganglion in the periaortic soft tissue (left).

 

 

【 Fig. 50-2 (LP)】False lumen (upper) with irregular surface and blood clots, while true lumen (low) with endothelial lining; note atherosclerotic change in the wall (right lower).

　

 

【 Fig. 50-3 (HP)】Detail of atherosclerotic change of wall with cholesterol-laden macrophages (foamy histiocytes).