Vascular malformations

From Libre Pathology
(Redirected from AVM)
Jump to: navigation, search

Vascular malformations come in different flavours.

Types:[1]

  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

Gross

Features:[1]

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

Image:

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.
  • 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

www:

Sign out

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.[3]

Images:


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:

Microscopic

Features:[5]

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

DDx:

Images:


Capillary teleangiectasia

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

Microscopy

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

Images:

See also

References

  1. 1.0 1.1 Prayson RA, Kleinschmidt-DeMasters BK (November 2006). "An algorithmic approach to the brain biopsy--part II". Arch. Pathol. Lab. Med. 130 (11): 1639–48. PMID 17076525.
  2. Marchuk, DA.; Srinivasan, S.; Squire, TL.; Zawistowski, JS. (Apr 2003). "Vascular morphogenesis: tales of two syndromes.". Hum Mol Genet 12 Spec No 1: R97-112. PMID 12668602.
  3. MUN. 23 November 2010.
  4. 4.0 4.1 URL:: http://missinglink.ucsf.edu/lm/DermatologyGlossary/cherry_angioma.html. Accessed on: 13 August 2012.
  5. Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 546. ISBN 978-0443066542.
  6. Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 551. ISBN 978-0443066542.