Difference between revisions of "Vascular malformations"
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*Vessels back-to-back/little intervening parenchyma. | *Vessels back-to-back/little intervening parenchyma. | ||
**Muscle is absent in the vessel walls - '''key feature'''.<ref>MUN. 23 November 2010.</ref> | **Muscle is absent in the vessel walls - '''key feature'''.<ref>MUN. 23 November 2010.</ref> | ||
==See also== | |||
*[[Neuropathology]]. | |||
*[[Vascular tumours]]. | |||
*[[Vasculitis]]. | |||
==References== | ==References== | ||
Revision as of 17:38, 18 May 2011
Vascular malformations come in different flavours.
Types:[1]
- Arteriovenous malformation.
- Most important clinically - highest risk of bleeding.
- Varix.
- One large (dilated) vein.
- Venous angioma.
- Many small veins.
- Caverous malformation.
- Vessels are back-to-back (no intervening parenchyma).
Also see: Sturge-Weber syndrome.
Arteriovenous malformation
General
- High risk for bleeding vis-a-vis other vascular malformations.
Gross
Features:[1]
- Classically wedge-shaped - with base toward superficial aspect and apex toward deep aspect (like pulmonary infarcts).
- Usually middle cerebral artery distribution.
Microscopic
Features:
- Large vessels with eccentric wall thickening.
- "Large" = ~ 0.5 mm (0.25-1.0 mm).
- 0.25 mm = ~ 31 RBC diameters across.
- "Large" = ~ 0.5 mm (0.25-1.0 mm).
Image: Cerebral AVM (WC).
Notes:
- There is usually one feeding artery.
- The artery is often not seen.
- Arteries have a well-defined internal elastic lamina and an external elastic lamina (best seen on elastic trichrome).
- Veins do not have an external elastic lamina and have a poorly developed/thin internal elastic lamina.
Cavernous angioma
General
- Usually diagnosed by radiology.
Microscopic
Features:
- Vessels back-to-back/little intervening parenchyma.
- Muscle is absent in the vessel walls - key feature.[2]