Cavernous Malformation

INTRODUCTION: Cerebral cavernous malformations are angiographically occult lesions that consist of dilated sinusoidal channels lined by a single layer of endothelium without any intervening normal tissue, smooth muscle cells, or elastin. Cavernomas account for 10% to 15% of all vascular malformations. It is estimated that 1 in every 200 to 250 people, or approximately 34 million individuals worldwide, are affected by cavernous malformations (0.37% to 0.5% of the population). Cavernous malformations occur in two forms: spontaneous and familial. This lesion occurs throughout the central nervous system; 80% supratentorial, 15% brainstem and basal ganglia, and 5% spinal cord.

CASE DETAILS: A 36-year-old male without any comorbidities consulted Dr. Maulik Vaja at Sterling Hospital, Vadodara. He had developed sudden onset right-sided partial paralysis more in the upper limb than the lower limb for one month. On evaluation with MRI brain, he was found to have a subcortical lesion in the left posterior frontal lobe which bled and developed surrounding edema (Image 1).

Radiological findings were in favor of a cavernous malformation (subtype 2) in the pre-Rolandic area. He was advised options of surgery versus observation. The most untoward disadvantage of observation is rebleeding with subsequent attacks of hemiplegia, which eventually may turn into irreversible neurological deficit. On the contrary, surgical management can prevent rebleeding and its consequences. For the evaluation of the relation of the lesion with the corticospinal track (eloquent motor cortex), functional MRI brain was done (Image 2 & 3).

After that, he was advised for surgical resection of the lesion under intraoperative neuromonitoring/cortical mapping to reduce the risk of iatrogenic neurological deficit, mainly right hemiplegia. With preoperative workup and due consent for surgery, he underwent craniotomy and trans-sulcal resection of the subcortical lesion under total intravenous anesthesia and cortical mapping. Postoperatively, the patient was observed in ICU for 72 hours and shifted to a room for further management. The patient developed transient worsening of right-sided power which recovered completely over 3 weeks with physiotherapy and antiedema measures (Images 4 & 5).

DISCUSSION: Appropriate management of patients with cavernous malformation requires a thorough understanding of the epidemiology and natural history of these lesions. Seizure and neurological deficit are the most common presenting symptoms secondary to recurrent hemorrhages in the lesion. When deficits develop after the first episode of symptomatic hemorrhage, they are often transient, resolving over days to weeks as the blood is absorbed. In contrast, recurrent episodes of hemorrhage are apt to be associated with progressively more severe deficits and an increased risk for permanent neurological impairment. Kim and associates observed the incidence of recurrent hemorrhage at a rate of 2.3% per patient per year. In our case, the young age of the patient increases the risk of rebleeding in productive years of life. Radiologically, these lesions can be divided into four different subtypes. Aiba and colleagues observed types 1 & 2 variety of cavernoma to have a risk for recurrent symptomatic hemorrhage of 22.3% per lesion-year. The symptomatic presentation of the patient and the location of the cavernous malformation dictate the need for surgical intervention. Asymptomatic patients with an incidentally diagnosed cavernoma are managed conservatively. Asymptomatic lobar and cerebellar lesions with no relation to the eloquent cortex are generally at low surgical risk, and patients can be offered resection versus observation. Lesions located in the eloquent cortex should be evaluated with fMRI, and resection tailored appropriately. If presenting symptoms are mild and the lesion localizes within the eloquent cortex, then observation can be considered, provided the risk of repeated hemorrhages may lead to worsening or irreversible deficit. The goal of surgical intervention for all cavernoma patients is complete surgical resection while minimizing the risk of a postoperative neurological deficit. Cavernous malformations in eloquent locations have a relatively high risk of immediate postoperative worsening of neurological deficits. This rate has been reported to range from approximately 30% to 60% of patients. The risk of neuro deficit can significantly be reduced with the use of neuromonitoring. However, the majority of patients experience neurological improvement. Long-term follow-up has reported worsening neurological deficits in approximately 5% to 16% of patients compared with their preoperative status. Total resection of eloquent cavernous malformations is typically reported in more than 90% of cases.

CONCLUSION: Cavernous malformations are relatively common lesions that affect 0.4% to 0.5% of the population. The modality of management of cavernous malformations is related to their presentation (symptomatic or asymptomatic), imaging characteristics, and location of the lesions. The risk for recurrent symptomatic hemorrhage is higher in patients with symptomatic lesions and radiological subtype 1 and 2 at a rate up to 30%. Lesions located in the eloquent cortex can be surgically excised successfully rather than exposed to the risk of rebleeding and further neurological deterioration. With the advent of advanced Preoperative evaluating tools like functional MRI and intraoperative tools like cortical mapping, the safety and efficacy of surgery can be increased much more.