This document discusses various types of vascular malformations of the brain. It begins by describing the histopathology and classification of arteriovenous malformations (AVMs), venous angiomas, capillary telangiectasias, and cavernous malformations. It then covers the pathology, clinical features, diagnosis using angiography, and treatment options for AVMs including surgery, radiosurgery, and endovascular embolization. It also discusses dural arteriovenous fistulas, carotid cavernous fistulas, vein of Galen malformations, developmental venous anomalies, cavernous malformations, capillary telangiectasias, and sinus pericranii.

1. VASCULAR
MALFORMATIONS
OF BRAIN

2. HISTOPATHOLOGY
AVM Venous Angioma
Capillary
Telangiectasia
Cavernous
malformation
CLASSIFICATION

3. FUNCTIONAL
AV
SHUNTING
AVM
Dural Av
Fistula
VOG
malformation
WITHOUT AV
SHUNTING
Venous
angioma
Capillary
telangiectasia
Cavernous
malformation
Sinus
pericranii
CLASSIFICATION

4. AV MALFORMATION
• MC
• Usually congenital
• Tightly packed thin walled vessels (NIDUS)
• Direct artery to vein shunting
• No intervening capillary bed
• Most AVMs are parenchymal lesions – aka PIAL AVMs

5. PATHOLOGY
• LOCATION: supratentorial(85%)
• SIZE : 2-6cms in diameter
• NUMBER : solitary (<2%multiple)
• Multiple when a/w syndromes HHT , Wyburn-Mason syndrome

6. CLINICAL FEATURES
• Presentation: 2-4th decade
• Headache with H’age – MC
• Seizures > hemorrhage(adults )
• Seizures < hemorrhage(children )
Nidus – MC site for hemorrhage
Location – peri/interventricular /basal ganglia
• Focal neurological deficits(20-25%)
STEAL from adjacent normal area
Mass effect

7. PROGNOSIS
• All are potentially hazardous
• Lifelong risk of H’age- 2-4% every year cumulative
• Spontaneous regression – rare and unpredictable

8. ANGIOGRAPHY
• Internal angioarchitecture best depiction.
• Depicts 3 components of AVM
– Enlarged arteries+/- aneurysm
– Nidus
– Early draining veins

9. FEEDING ARTERIES
• Dilated and tortuous.
• Flow related angiopathy – dilatation , stenosis or thrombosis.
• Pedicle aneurysm(10-15%cases).

10. NIDUS
• Tightly packed tangle of abnormal arteries and veins with no
intervening capillary bed/brain parenchym.
• Intranidal aneurysm(50% cases)

11. DRAINING VEINS
• Opacify in mid-late arterial phase(Early draining vein)
• Enlarged , tortuous and may form varices exerting local mass effect.
• Stenosis can cause AVM H’age by ↑ intranidal pressure.

12. TREATMENT
• Complete obliteration of nidus for cure.
• Traditonal Rx – Surgical excision for nidus.
• Acute and emergent surgical intervention – in life threatening ICH

13. STEREOTACTIC RADIOSURGERY
• Focussed irradiation to nidus
• Indication
– Unresectable because of location
– Size < 3.5cms
• Adv : Non invasive
• Disadv :Effect takes years
Risk of h’age till it disappears completely

14. ENDOVASCULAR RX
• Adjunct to Sx/ RadioSx
• Used in small AVMs or 1-2 feeding arteries
• Embolisation – Precedes surgery /radiosx reduce size of nidus
• Complete cure if : small AVM , few feeders , single draining vein

15. DURAL AV FISTULA
• 2nd MC CVM with AV shunting
• Tiny crack like vessels that shunt blood b/w meningeal arteries and
small venules within dural sinus wall.
• Etiology : Acquired – ↑ angiogenesis within dural sinus wall after
thrombosis.

16. PATHOLOGY
• LOCATION: Trans Sinus>Sig sinus>Cav sinus(adults)
Sup Sigmoid sinus (Children)
• SIZE : Tiny single vessel shunts to massive complex lesions with multiple
feeders.
• NUMBER : Multiple lesions are uncommon

17. CLINICAL FEATURE
• Mostly in adults(40-60yrs)
• C/F varies wht location and drainage pattern
TS-SigS - Bruit and tinnitus
Cav S – Pulsatile proptosis , chemsois , retroorbital Pain
• Lesions with cortical venous drainage(Malignant dAVF) : seizures,
dementia , progressive FND

18. PROGNOSIS
• 98% w/o cortical venous drainage - benign course.
• Malignant dAVF – aggressive clinical course with H’age and ND.
• Multiple dAVF – poor clinical prognosis

19. TREATMENT
• Conservative – Observation +/- carotid compression technique.
If rsk of H’age
• Endovascular – Embolisation of arterial feeders with particulate or liquid
agents , coil embolization of venous sinus.
• Surgical resection of involved dural venous sinus.
• Stereotactic RadioSx- 2-3 years for obliteration.

20. CAROTID CAVERNOUS FISTULA
• AV shunting developing within cavernous sinus.
• Direct
– High Flow
– Rupture of cavernous ICA into CS
• Indirect
– Slow flow , low pressure
– Fistula b/w dural br of ICA and the CS

21. ETIOLOGY
• Almost always acquired
• Direct
– Traumatic: central skull base #
– Non-Traumatic: Preexisting cavernous ICA aneurysm
• Indirect
– Degenerative – sequelae of dural sinus thrombosis

22. PATHOLOGY
• GROSS
– Dilated CS (Direct CCF)
– Enlarged crack like vessels(Indirect)

23. VEIN OF GALEN ANEURYSMAL MALFORMATION
• Direct AV fistula b/w deep choroidal arteries and persistent embryonic
precursor of VOG.
• Large midline venous pouch behind the 3rd ventricle.
• MC extracardiac cause of high-output cardiac failure in newborn.

24. • In normal fetal dvpt : arterial supply of choroid plexus drains via single
transient midline vein – median prosencephalic vein.
• Internal cerebral vein drains fetal chorid plexus as MPV regresses.
• Persistent high flow fistula prevents regression.

25. CLINICAL FEATURES
• >30% of symptomatic VM in children
• Rare in adults
• Neonates – high output CCF with cranial bruit
• Older infants – macrocrania + hydrocephalus +/- CCF
• Older Children – Developmental delay and seizures
• Young adults – Headache
• Large VGAMS – cerebral ischemia and dystrophic changes
• Left untreated – Die of progressive brain damage and intracatable CCF

26. TREATMENT
• Goal – not anatomic cure of VGAM but control malformation to allow
normal brain dvpt.
• Staged arterial embolization at 4/5m

27. WITHOUT AV SHUNTING

28. DEVELOPMENTAL VENOUS ANOMALY
• Venous angioma/venous malformation
• Umbrella shaped CVM with mature venous part.
• No arterial component
• May represent anatomic variant of otherwise normal venous drainage

29. CLINICAL FEATURES
• Usually asymptomatic
• Headache/seizures
• H’age with FND ( if a/w cavernous malformation)
• MC vascular malformation at autopsy

30. TREATMENT
• Solitary DVA – no Rx
• Histologically mixed – based on coexisting lesion

31. CAVERNOUS MALFORMATIONS
• They are composed of thin-walled, blood-filled sinusoidal locules known
as “caverns,”.
• Angiographically occult.
• Low-pressure systems.

32. • They are a distinct form of vascular malformation in comparison to
arteriovenous malformations > do not have any intervening brain parenchyma
within the lesion.
• These lesions were once known as “cavernomas,” which was predicated by the
misconception of them representing vascular tumors.
• The lesions were noted to grow over time > this increase in size is related to
recurrent hemorrhages.
• These hemorrhages occur as a result of the immature angiogenic nature of these
lesions.

33. • CMs were once generally believed to be congenital in nature; > there is
compelling evidence that they can occur through de novo formation as well.
• Sporadically as isolated lesions or in clusters, as noted in the familial forms of
the disease(an autosomal-dominant phenotype in familial forms of the disease).
• De novo formation of CMs has been well documented secondary to effects of
radiation exposure.
• CCM gene .

34. • CCM1 (K-Rev interaction trapped 1 (KRIT1))
• CCM2 (MGC4607/osmosensing scaffold for MEKK3/malcavernin)
• CCM3 (programmed cell death 10 (PDCD10)) genes are expressed as
autosomal-dominant phenotypes with penetrance of 60–80%, 100%, and 63%
respectively.
Mutations in the CCM genes are hypothesized to result in a loss of function of
cell signaling compromising endothelium integrity and abnormal angiogenesis,
producing the vascular pathology observed in CM lesions.

35. • Abnormal structural integrity of the vasculature of CM lesions.
• Vessels are immature with poorly differentiated vascular smooth-muscle cells
that give rise to the development of dysmorphic vessel walls that are prone to
hemorrhage, thus further activating dys-angiogenesis and lesion proliferation.
• Ultra structural analysis of the vasculature in CMs has demonstrated that the
endothelial cells within the vessel wall have defective interendothelial tight
junctions, rendering the vasculature permeable and blood–brain barrier
incompetent.

36. • Gross specimens of CMs have the appearance of a reddish-purple raspberry
due to the collection of blood-filled caverns.
• They are typically well circumscribed and lobulated lesions.
• The surrounding cortex is usually hemosiderin stained as a result of prior
hemorrhage.
• Recurrent hemorrhages lead to superficial siderosis of the leptominges that can
be grossly apparent.

37. • The hemosiderin staining of the surrounding cortex can be helpful for
localization of CMs during resection.
• Within the lesion there is no intervening brain parenchyma.
• Blood in the caverns may be of various ages.
• Microscopic examination of CMs demonstrates the typical features of vascular
sinusoids or “caverns” lined by endothelial cells.
• Red blood cells are commonly visualized inside of the caverns

38. • In between the caverns there is usually a dense connective-tissue matrix that is
composed of fibroblasts.
• Within the stroma and surrounding periphery of the CM lesion hemosiderin
staining can be found as evidence of prior hemorrhage.
• Commonly, reactive gliosis can be observed in the brain parenchyma abutting
the lesion.
• Occasionally, calcium deposition can also be noted.
• Immunohistochemistry is particularly useful in identifying the vascular
endothelium and subsequently illustrates the presence of CCM proteins within
the vascular endothelium.

39. CAPILLARY TELANGIECTASIA
• Capillary angioma
• Collection of enlarged thin walled vessels resembling capillaries.
• Vessels surrounded by normal brain parenchyma
• Probably congenital lesions
• MC sites : Pons , cerebellum(can occur anywhere)

40. CLINICAL FEATURES
• Peak Presentation : 30-40 years
• Usually silent, discovered incidentally at imaging

41. SINUS PERICRANII
• Large transcalvarial communication between intra and extra-cranial venous
drainage system.
• Mostly congenital.
• May be a/w other dva.

42. CLINICAL FEATURES
• Rare.
• Children and young adults.
• Non tender non pulsatile bluish compressible scalp mass.
• Increase in size with Valsalva.
• Reduce on upright position

43. TREATMENT
• Surgical removal of extra cranial component cosmetic purpose.