Vascular malformations

Vascular malformations come in different flavours.

Types:

1. Arteriovenous malformation.
   • Most important clinically - highest risk of bleeding.
2. Varix.
   • One large (dilated) vein.
3. Venous angioma.
   • Many small veins.
4. Cavernous hemangioma (Cavernoma).
   • Vessels are back-to-back (no intervening parenchyma).
5. Capillary teleangiectasia
   • Small capillaries

Also see: Sturge-Weber syndrome.

Arteriovenous malformation

• Abbreviated AVM.

General

• High risk for bleeding vis-a-vis other vascular malformations.
• May be seen in the context of hereditary hemorrhagic telangiectasia.

Gross

Features:

• Classically wedge-shaped - with base toward superficial aspect and apex toward deep aspect (like pulmonary infarcts).
• Usually middle cerebral artery distribution.

Image:

• AVM (flickr.com).

Clinical DDx:

• Melanocytic lesion.
• Other vascular lesions.

Microscopic

Features:

• Large vessels with eccentric wall thickening.
  • "Large" = ~ 0.5 mm (0.25-1.0 mm).
    • 0.25 mm = ~ 31 RBC diameters across.

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.

DDx:

• Other vascular lesions.

Images

• 

  Cerebral AVM. (WC)

www:

• AVM - several images (upmc.edu).

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ANUS, BIOPSY:
- ARTERIOVENOUS MALFORMATION (PROMINENT SUPERFICIAL DERMAL ARTERIES AND VEINS).
- SKIN WITH PARAKERATOSIS.
- NEGATIVE FOR MELANOCYTIC LESION.
- NEGATIVE FOR MALIGNANCY.

ANUS, BIOPSY:
- SKIN WITH PARAKERATOSIS.
- PROMINENT SUPERFICIAL DERMAL ARTERIES AND VEINS -- COMPATIBLE WITH
  ARTERIOVENOUS MALFORMATION.
- NEGATIVE FOR MELANOCYTIC LESION.
- NEGATIVE FOR MALIGNANCY.

Cavernous hemangioma

General

• Usually diagnosed by radiology.
• Clinicians call it cavernoma.

Microscopic

Features:

• Vessels back-to-back/little intervening parenchyma.
  • Muscle is absent in the vessel walls - key feature.

Images:

• 

  Cavernous hemangioma (WC/Patho82).

• 

  Cavernous hemangioma of the liver (WC).

Venous angioma

General

• Subcortical white matter.
• Most common vascular malformation found at autopsy.

Gross

• May look like petechial hemorrhages.

Microscopy

• Thin walled, dilated vascular channels.
• Lesions larger than capillary teleangiectasia.

Cherry angioma

• AKA Campbell De Morgan spots.
• AKA senile angioma.
• AKA cherry hemangioma.

General

• Benign.
• Common in the elderly.

Clincal:

• Red spot.
• Polypoid.

Gross

• Red spot - well demarcated.

Image:

• Cherry angioma (ucsf.edu).

Microscopic

Features:

• Superficial polypoid lesion that is well-circumscribed.
• Abundant capillaries - key feature.

DDx:

• Venous lake - single vessel.
• Hemangioma.

Images:

• Cherry hemangioma (dermpathexpert.com).
• Cherry angioma (ucsf.edu).

Capillary teleangiectasia

• Usually incidental finding at autopsy.
• Pons as predilection site.

Microscopy

• Many small, thin walled capillaries surrounded by normal brain.
• No hemorrhage.

Images:

• 

  CNS teleangiectasia

See also

• Neuropathology.
• Vascular tumours.
• Vasculitis.
• Littoral cell angioma.