Characteristics and treatment of cavernous malformations

Abstract

Cavernous malformations are clusters of dilated sinusoidal channels with thin walls devoid of elastin and smooth muscle. They have no intervening brain tissue. They occur both in sporadic and familial forms. The genes responsible for cavernous malformations have been identified. Recent reports show that mutations of these responsible genes are involved not only in familial but also in sporadic forms. Germline and somatic mutations may occur before cavernous malformations develop (two-hit mechanism). Two patterns, with mulberry-like and hematoma-like appearances, are seen intraoperatively, and from histological findings, mulberry-like appearance may change into hematoma-like one by intralesional hemorrhage. Cavernous malformation treatments include open surgery and radiosurgery. Open surgery is usually chosen for the treatment of symptomatic hemorrhagic cavernous malformations because post-radiosurgical annual bleeding risks at the early phase seem to be higher than those of open surgery. If open surgery has a high risk because of lesion location, radiosurgery becomes an effective alternative treatment. Brainstem cavernous malformations have high annual bleeding and re-bleeding incidence, so if the lesion is accessible with low risk, open surgery is recommended.