1. Extra-cerebral Intracranial Cavernous Malformations: MRI findings in 27 patients.
Mauricio Castillo, MD, FACR,
Hortensia Alvarez, MD
University of North Carolina at Chapel Hill

2. Abstract
Objective: to review imaging/clinical findings in patients with extra-cerebral intracranial cavernous malformations (CM).
From our TF database we extracted 28 patients with extra-cerebral intracranial CM. All had MRI with at least pre-contrast T1, T2 images & post Gd T1.
13/27 patients underwent resection with confirmation of diagnosis.

3. Findings Patients age: 1 week to 55 years Gender: 22 males, 6 females
CM size: 1-12 cm
Largest ones in children and those in trigones of lateral ventricles
Associated vascular anomalies:
DVAs in 4 patients
Veno-sinus malformation in 1 patient

4. Most common locations of CM in our patients.
Findings
Locations:
Intraventricular: 13
5 in 3rd ventricle, 1 in 4th, 7 in lateral ventricles
2 patients had multiple cerebral CM syndrome
Dural (convexities): 7
Middle fossae: 2
Falx cerebri: 4
Cavernous sinus: 1
IAC: 1
Most common locations of CM in our patients.

5. Symptoms and Management
Most common symptoms:
Hydrocephalus: 6
Seizures: 8
Headaches: 2
Others: 11
Surgical resection for all those that produced seizures & 2 with focal neurological deficits.
Resection or biopsy for all patients with hydrocephalus.

6. CM, General Facts
Occur in 0.5% of the population, account for 15% of all cerebral vascular malformations.
80% supratentorial, 20% infratentorial, 15% of all CM are extra-axial.
50-75% of patients are eventually symptomatic:
40-70% have seizures,
35-50% have focal deficits,
10-30% have headaches,
Hemorrhage is rare (more common in children).
Solitary lesions do not exclude familial syndrome.

7. CM- Treatment
Surgery reserved for patients with seizures/focal deficits unresponsive to other therapies & those with CM in accessible regions.
Re-operations are rare.
Gamma-knife/radiosurgery while effective increases risk of hemorrhage.
Aspirin, NSAD, heparin, warfarin may increase risk of bleeding.

8. MRI-Pathology-Clinical Correlations
Type
MRI
Histology
Clinical 1
T1 & T2 bright core
Subacute blood
Generally symptomatic, may re-bleed 2
T1 & T2 complex core, hypointense halo
Bleeds & thromboses
May be either symptomatic or asymptomatic 3
T1 & T2 hypointense core & halo
Chronic bleeds 4
T1 hypointense core, T2 hyperintense/complex core, low signal halo
Vascular channels & stroma, no acute/subacute bleeds 5
Punctate hypointense lesions on SWI/GRE
Tiny CM or capillary telangiectasia
Asymptomatic, true new lesions
Adapted & modified from Zabramski & de Souza.

9. Histopathology. CM are vascular malformations consisting of closely clustered, enlarged capillary channels (caverns) with a single layer of endothelium without normal mature vessel wall elements or intervening brain. Thrombosis & intra- and extra-lesional hemorrhage may be present. Edema may surround lesions with recent hemorrhage.

10. Intraventricular-ependymal
Comprise 2.5% of all cerebral CM.
Diagnosis is difficult by imaging & thus resection may be indicated; ependymal siderosis may suggest correct diagnosis.
Of about 60 cases of intraventricular CMs reported in the literature, 17 occurred in trigones.
Trigone CM may be large (especially in children).

11. 4th ventricular type 2 CM in a 43-year-man
4th ventricular type 2 CM in a 43-year-man. Axial T2 & FLAIR images show rounded, centrally complex & peripherally low signal lesion (arrows) in obex of 4th ventricle which resulted in hydrocephalus. The mass was surgically resected.

12. Right trigone type 2 CM in a 40-year-old man
Right trigone type 2 CM in a 40-year-old man. Axial T1 post Gd (left), pre Gd parasagittal T1 (center) & axial T2 (right) show complex appearing mass which was biopsied but not resected. Note large subependymal component of associated DVA (arrow). Smaller CM is present anterior to frontal horn of right lateral ventricle.

13. 1-week-old male with intraventricular type 2 CM
1-week-old male with intraventricular type 2 CM. A large complex mass is located in the right trigone. Note large medial DVA (right parasagittal images). The mass was surgically resected.

14. 3 patients, 20-year-old female (left), 32-year-old male (center) & 29-year-old female with 3rd ventricular CM (arrows). Masses in first 2 patients resulted in hydrocephalus & were surgically resected. CM have complex appearances (type 2), center patient shows left periventricular edema.

15. 28-year-old male shows 3rd ventricular type 2 CM with obstruction of the foramina of Monro & dilatation of the lateral ventricles.

16. A B C D
27-year-old man. Coronal T1 post Gd (A), axial T1 post Gd (B), FLAIR (C) & T2 (D) images show a CM in the frontal horn of the left lateral ventricle. This type 2 CM shows minimal contrast enhancement & a peripheral rim of low signal.

17. 45-year-old man. Axial FLAIR & T2 images show CM in the subependymal region of the left frontal horn of the lateral ventricle. This type 2 CM shows a halo of low T2 signal.

18. Two males with familial cerebral CM syndrome
Two males with familial cerebral CM syndrome. In both patients (35 [left]& 26 [above[ years-old) MR images show one CM in the frontal horns of the right lateral ventricles each as well as multiple cerebral CV. Type 2 CM.

19. A B C D
6-year-old boy with right trigone type 4 CM on T1 pre Gd & T2 images (A,B). SWI (C) shows DVA adjacent to right frontal horn & post Gd sagittal T1 image (D) shows a malformation of the superior sagittal sinus with a persistent & large falcine sinus.

20. Dural CM
Only few cases reported, generally indistinguishable from meningioma by MRI:
May show dural “tails” of contrast enhancement,
High T2 signal suggests diagnosis of CM.
Most occur in middle age (45-65 years) women.
Most in falx cerebri, lateral cavernous sinus walls, tentorium & falx cerebelli.
ICA CM are extremely unusual, imaging diagnosis is difficult in small ones
Those in middle cranial fossa may erode bone.
Highly vascularized & bloody at surgery.

21. 2 patients with dural-based type 2 CM
2 patients with dural-based type 2 CM. MR images shows CM in the right middle cranial fossae (left: 33-year-old man, right: 28-year-old woman). Both were resected as they resulted in seizures.

22. 3 male patients (27-year-old, 45 years old, 39-year-old, left-to-right). MR images show variable appearance of peripherally located CM which were resected due to seizures. All 3 were extra-axial & arose from the meninges. Center is type 3, other two are type 2.

23. Type 2 CM in a 21-year-old male with chronic intractable epilepsy
Type 2 CM in a 21-year-old male with chronic intractable epilepsy. Extra axial location was confirmed at surgery.

24. CT & MR images in a 35-year-old man with seizures show a mostly T1 hypointense, T2 bright & homogeneously contrast enhancing mass in the right parietal region. Pathology confirmed diagnosis of type 5 CM. (from: Vogler & Castillo. AJNR 1995; 16: 773)

25. Falx CM
2 patients with anterior falcine type 2 CM resected due to seizures. Both show hypointense T2 halo (left: 43-year-old man, right: 51-year-old man)

26. 18-month-old boy with seizures
18-month-old boy with seizures. T1 post Gd & T2 images show complex type 2 CM in left medial occipital region. At surgery, the mass was extra-axial & adherent to the falx.

27. 55-year-old female with breast cancer
55-year-old female with breast cancer. MR images show left para-falcine mass thought to be a meningioma & followed for 11 years. The mass showed minimal growth during the last year and was thus resected. The type 5 CM was adherent to the falx and extra-axial. Note high T2 signal (arrow).

28. Cavernous Sinus CM
45-year-old woman with a left CN III palsy. Top row: MR images show an enhancing mass (arrows) centered in the left cavernous sinus. Note high T2 signal. Bottom row: coronal dynamic contrast enhanced T1 images show peripheral filling in of the mass typical of a CM in this region. Type 5 CM.

29. ICA CM
25-year-old female with hearing loss. T2 (left), T2* (center) and T1 post contrast (right) images show the typical appearance of a cavernoma in the CPA cistern extending into the IAC. Chronic blood products are seen in the cerebellum. Type 2 lesion.
Courtesy A. Pajon, Bogota, Colombia

30. Conclusions
In our series, CM were type 2 (n=22), type 4 (n=4) & type 5 (n=2).
26 had MRI features that suggested or made the correct diagnosis.
All dural-based CM were symptomatic & resected (50% of all CM were symptomatic).
Patients age & lesion sizes varied widely, most CM occurred in males.
Associated venous anomalies were less common than reported with intracerebral CM (14% vs %).
Exact prevalence of extra-cerebral, intra-cranial CM could not be established as this was a retrospective review.

31. References
Morrison L, Akers A. Cerebral cavernous malformation, familial. GeneReviews
Zabramski JM, Wascher TM, Spetzler RF, Johnson B et al. The natural history of familial cavernous malformations: results of an ongoing study. J Neurosurg. 1994;80:422–32
de Souza JM, Domingues RC, Cruz LC, Domingues FS et al. Susceptibility-weighted imaging for the evaluation of patients with familial cerebral cavernous malformations: a comparison with t2-weighted fast spin-echo and gradient-echo sequences. AJNR Am J Neuroradiol. 2008;29:154–8.
Sabat SB. Intraventricular cavernous malformation with superficial siderosis. Arch Neurol 2010; 67: 638-9

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