Vascular Disease 3: Vascular anomalies

Last updated on Friday, April 17 2009 by gliageek

Arteriovenous malformations (AVMs) are the most clinically significant of the congenital vascular malformations (the others are less likely to become symptomatic and are more frequently incidental findings on examination of the brain for other reasons). AVMs are congenital arterio-venous shunts or connections without intervening capillary beds. Two thirds are diagnosed before the age of forty. Ninety percent are in the cerebral hemispheres and most of these are in the middle cerebral artery distribution. AVMs tend to present either with intracerebral hemorrhages or seizures.

Welsh, Cynthia T. Vascular Lesions of the Nervous System. Pathology Case Reviews: November/December 2008 - Volume 13 - Issue 6 - pp 241-246

Related images:

Arteriovenous malformation, coronal section, close-up
Large caliber vessels and small amounts of intervening discolored brain parenchyma.

Arteriovenous valve formation, coronal section through parietal lobe
Arteriovenous malformation within subcortical white matter.

Arteriovenous malformation, coronal section through posterior parietal lobe
Large caliber blood vessels with small amounts of abnormal intervening brain parenchyma. Dilated draining vein can be seen with difficulty entering leptomeninges on the convexity of the brain

Cavernous angioma, ventral surface of brain, close-up
A cavernous angioma can be seen obscuring the right cerebral peduncle in the midbrain.

Cavernous angioma, H&E stain slide
Cavernous angiomas are characterized by dilated, thickened blood vessels lacking elastic lamina and without intervening brain parenchyma

Cavernous angioma with dystrophic ossification, H&E stain x 100
Ossification can be seen along the right side of the photograph.

Cavernous angioma, trichrome stained section x 40
Trichrome staining demonstrates absence of smooth muscle within the back to back dilated vessels of the angioma.

Cavernous angioma, H&E stain x 100
The angioma nidus is characterized by a back-to-back blood vessels without intervening brain parenchyma

Cavernous angioma, H&E stained slide x 400
Back to back hyalinized vascular channels. Hemosiderin laden macrophages can be seen at the bottom right corner of the photograph

Multiple cavernous angiomas, coronal section of brain through basal ganglia and transverse section of pons.
Unlike most of the other vascular malformations, cavernous angiomas may occur as a familial trait in which cases they are often multiple.

Superficial siderosis, sagittal section through cerebellar vermis
Superficial siderosis occurs in patients with chronic subarachnoid bleeding. Heme metabolites accumulate at the base of the brain, where there are toxic Purkinje cells, resulting in cerebellar degeneration with ataxia

Multiple cavernous angiomas, transverse section of pons, close-up
Unlike most of the other vascular malformations, cavernous angiomas may occur as a familial trait in which cases they are often multiple. The absence of associated edema distinguishes these lesions from hemorrhagic metastases, such as may be seen in patients...

Foix-Alajounine syndrome, transverse section through spinal cord.
Foix-Alajounine syndrome, also known as vascular congestive myelopathy, occurs when spinal cord function is impaired due to vascular congestion secondary to venous congestion within the spinal cord which may in turn be secondary to the presence of a dural AV fistula.

Capillary Telangiectasis, left insular cortex, coronal section, close-up
Dusky discoloration is due to dilatation of capillary sized blood vessels.

Arteriovenous malformation, H&E stain x 20
Abnormal arterial type vessels participate in this malformation

Venous angioma (malformation), H&E stain slide
Compensatory dilatation of venous channels secondary to hypoplasia of the regional venous circulation. Resection is accompanied by a very high risk of consequent venous infarction.

Review of the relevant anatomy