• cerebral cavernous malformation (CCM) is a well-circumscribed accumulation of dilated thin-walled vessels affecting the brain
    • only a layer of endothelium and subendothelial stroma is present; there are no smooth muscle cells and elastic fibers
    • the pathogenesis of CM remains unclear
  • forms:
    • sporadic
      • incidence in the population 0.4-0.9% [Sage, 1993]
      • accounts for 8-15% of all vascular malformations
      • usually one lesion (in about 70% of cases)
    • familial
      • a genetically linked multiple cavernomatosis (AD)  Multiple cerebral cavernomatosis (SWI)
      • more often symptomatic
      • possible de novo CM formation
  • can be localized anywhere (approximately 80% are supratentorial)
  • CM associated anomalies:
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Cavernous malformation

Pathophysiology

  • erythrocyte diapedesis through the pathological cavernoma wall
    • hemoglobin degradation products lead to pathological excitability, oxidative damage, and gliosis ⇒ epilepsy
  • bleeding into the cavernoma ⇒ ↑ malformation volume
  • bleeding into the surrounding area

Clinical presentation

  • clinically asymptomatic in up to 44% of cases
  • epileptic seizures (45-70%) [Májovský, 2014] [Sage, 1993]
    • mainly in lesions localized in the frontal and temporal lobe
    • cavernous malformations are cause of approximately 4% of refractory epilepsies
  • bleeding
    • low risk (0.25-0.7% per year), increased in case of previous bleeding (⇒ 4.5% / year)
    • higher risk in infratentorial lesions
    • hemorrhages are not fatal due to low pressure within the malformation; repeated hemorrhages, however, may ultimately lead to severe deficit
  • headache (20-30%)
  • focal neurological deficit (e.g., in case of cerebellar or brainstem lesion)
  • risk factors for adverse outcome
    • multiple lesions
    • CCM3 genotype
    • early clinical presentation
    • infratentorial localization
    • diameter >1 cm
    • associated venous anomaly (DVA)

Diagnostic evaluation

  • CT
    • usually poorly visible lesion (negative CT in up to 50% of cases)
    • the cavernous malformation may be slightly hyperdense, with small calcifications     Cavernous malformation
    • none or only minimal postcontrast enhancement Cavernous malformation - subtle enhancement on contrast CT
    • no mass effect, no collateral edema
    • recent bleeding may be detected
  • MRI (sensitivity 100%) Cavernous malformation  
    • popcorn appearance   Cavernous malformation - popcorn appearance
    • a heterogeneous lesion with hemosiderin rim (T2-hypointense) Cavernous malformation 
    • prominent finding on GRE – “blooming artifact”
    • slight enhancement is possible  [Pinker, 2006]
  • DSA is normal
Cavernous malformation (FLAIR)

Cavernous malformation
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  • the Zabramski MRI classification has been proposed as a way of classifying cerebral cavernous malformations
  • useful rather for scientific purposes
  • type I: subacute hemorrhage
    • T1: hyperintense
    • T2: hypo-/hyperintense
  • type II:  classic “popcorn” lesion  Cavernous malformation - popcorn appearance
    • T1 and T2: mixed-signal intensity centrally
    • T2*/GRE/SWI: hypointense rim with blooming
  • type III: chronic hemorrhage
    • T1: hypointense/isointense centrally
    • T2: hypointense centrally
    • T2*/GRE/SWI: hypointense rim with blooming
  • type IV: multiple punctate microhemorrhages
    • GRE/SWI: “black dots” with blooming
    • difficult to distinguish from small capillary telangiectasias

Management

Surgery and radiotherapy

  • microsurgical resection
    • relatively safe surgical procedure with low morbidity and mortality  [Májovský, 2014]
    • proved indications:
      • refractory epilepsy (up to 90% of patients are seizure free after the surgery)
      • recurrent bleeding
    • in infratentorial CMs, surgery is preferred in cerebellar lesions and bleeding lesions localized near the ventricle or cistern  [Amato, 2013]
  • stereotactic radiosurgery (SRS) may be considered for non-operable lesions [Liščák, 2013] [Liščák, 2000]
    • indications and therapy results are controversial
    • in contrast to AVMs, the direct effect of therapy can not be observed; long term clinical course may change compared to untreated lesions

Conservative therapy and follow-up

  • in asymptomatic lesions, perform a follow-up MRI every 1-2 years
  • keep blood pressure in normal range
  • beta-blockers might lower risk of intracranial hemorrhage or persistent/progressive focal neurological deficit in patients with CCM   (Zuurbier, 2022)
Management of cerebral cavernous malformation (CCM)
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