Management of Cranial Cavernous Malformations Depends on Location and Symptoms
Key findings
- Expectant management is appropriate for many asymptomatic cavernous malformations (CMs), depending on patient age and lesion location
- Patients with lobar CMs and seizures are managed initially with antiepileptic medications
- Surgical resection may be appropriate for cerebral and cerebellar CMs that hemorrhage, cause neurological deficits and are superficial in location
- For CMs in deep-seated or eloquent cortex, surgery is risky but may be considered if patients experience numerous hemorrhage events with neurological injury
- Management of brain stem CMs is controversial
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Cavernous malformations (CMs) of the brain and spinal cord account for 10-15% of central nervous system malformations. In appropriate cases, they can be surgically resected without a meaningful degree of hemorrhage because they are low-flow vascular malformations. Christopher J. Stapleton, MD, a neurosurgery resident at Mass General, and Frederick G. Barker, MD, a neurosurgeon at Mass General, recently reviewed current data on the management of CMs.
In Stroke, the authors note that, according to a recent meta-analysis, the most common clinical presentations of CMs are:
- Hemorrhage (36%)
- Incidental discovery (28.5%)
- Seizure (21%)
- Focal neurological defect (15%)
Risk factors for CM hemorrhage include young age, female gender, deep location and prior hemorrhage.
In one natural history study, the incidence of hemorrhage was 0.3% per patient-year for non–brain stem CMs and 2.8% per patient-year for brainstem CMs. Re-hemorrhage rates per patient-year were 6.3% and 32.3%, respectively. Hemorrhages tend to be small (<1.8 cm3), and most patients have good functional outcomes. The mortality rate after hemorrhage is low at 2.2%. The annual risk of hemorrhage declines after 2.5 years.
The incidence of new-onset seizures in patients already diagnosed with CM is estimated to be 1.5-2.4% per patient-year. Epilepsy develops in about 35-70% of patients with symptomatic CMs. Patients with lobar CMs and seizures should initially receive antiepileptic medication, but surgery is advisable for those with refractory seizures and neurological deficit.
Asymptomatic CMs can often be managed with watchful waiting. Even if a lesion is symptomatic, observation may be warranted if the risk of intervention outweighs the natural history risk of the lesion. There are still no well-accepted guidelines about the optimal frequency of cranial imaging while patients are being monitored.
Complete surgical resection is the gold standard intervention. For CMs in the cerebrum and cerebellum, surgical risk is typically low. Indications for surgery include multiple hemorrhages, neurological deficit and progressive seizures.
Cerebrum and cerebellum surgery for CMs in deep or eloquent supratentorial locations is quite risky. It remains controversial even though hemorrhage may result in progressive neurological deterioration. Still, patients with repeated hemorrhages, seizures or focal neurological deficits may be candidates for surgery.
Resection of brain stem CMs is even more controversial, but when patients are carefully selected by experienced neurovascular or skull base surgeons, acceptable outcomes have been achieved.
Some experts advocate stereotactic radiosurgery to stall the natural progression of CMs, but efficacy is not observed until two to three years later. In addition, high rates of radiation-induced injury have been reported.
Because the annual risk of hemorrhage declines after 2.5 years, Dr. Stapleton and Dr. Barker conclude that current evidence does not favor the use of stereotactic radiosurgery. Minimally invasive surgery for CM is on the horizon but still in the experimental stage.
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