Central nervous system cavernous hemangioma

Central nervous system cavernous hemangioma is a cavernous hemangioma that arises in the central nervous system (CNS). It can be considered to be a variant of hemangioma, and is characterized by grossly large dilated blood vessels and large vascular channels, less well circumscribed, and more involved with deep structures, with a single layer of endothelium and an absence of neuronal tissue within the lesions. These thinly walled vessels resemble sinusoidal cavities filled with stagnant blood. Blood vessels in patients with cerebral cavernous malformations (CCM) can range from a few millimeters to several centimeters in diameter. Most lesions occur in the brain, but any organ may be involved. Central nervous system cavernous hemangioma is a cavernous hemangioma that arises in the central nervous system (CNS). It can be considered to be a variant of hemangioma, and is characterized by grossly large dilated blood vessels and large vascular channels, less well circumscribed, and more involved with deep structures, with a single layer of endothelium and an absence of neuronal tissue within the lesions. These thinly walled vessels resemble sinusoidal cavities filled with stagnant blood. Blood vessels in patients with cerebral cavernous malformations (CCM) can range from a few millimeters to several centimeters in diameter. Most lesions occur in the brain, but any organ may be involved. Clinical symptoms of CNS origin include recurrent headaches, focal neurological deficits, hemorrhagic stroke, and seizures, but CCM can also be asymptomatic. The nature and severity of the symptoms depend on the lesion's location. In up to 30% there is a coincidence of CCM with a venous angioma, also known as a developmental venous anomaly (DVA). These lesions appear either as enhancing linear blood vessels or caput medusae, a radial orientation of small vessels that resemble the hair of Medusa from Greek mythology. These lesions are thought to represent developmental anomalies of normal venous drainage. These lesions should not be removed, as venous infarcts have been reported. When found in association with a CCM that needs resection, great care should be taken not to disrupt the angioma. Familial forms of CCM occur at four known genetic loci. The gene for CCM1 encodes KRIT1 (krev interaction trapped 1), and has been found to bind to ICAP1alpha (integrin cytoplasmic domain associated protein alpha), a beta1 integrin associated protein. A particular mutation in CCM1 (the Q455X mutation), accounts for a cluster of cases in the Southwestern United States. This cluster, particularly in northern New Mexico, is an example of the founder effect; it has been traced back to early Spanish settlers. The gene for CCM2 encodes a novel protein named malcavernin that contains a phosphotyrosine (PTB) binding domain. The exact biological function of CCM2 is not clear. Recently, it has been shown that CCM1 and CCM2 proteins as well as ICAP1alpha form a macromolecular complex in the cell. In addition, it appears that CCM2 protein may function as a scaffolding protein for MAP kinases that are essential in p38 activation responding to osmotic stress including MEKK3 and MKK3. It also binds to Rac and actin. Therefore, CCM2 protein is also called OSM (osmosensing scaffold for MEKK3). The CCM3 gene is the most recently identified CCM gene . CCM3 is known as PDCD10 (programmed cell death 10), which was initially identified as a gene that is up-regulated during the induction of apoptosis (cell death) in TF-1, a human myeloid cell line. The precise role of the PDCD10 protein in the CCM pathway is not clear. It is recently shown that PDCD10 forms a complex with CCM1 protein (KRIT1) and CCM2 protein (OSM). PDCD10 interacts directly with OSM independent of KRIT1-OSM interaction. Research is ongoing to determine the function and properties of all three CCM gene products as well as the reaction pathways in which they are involved. Evidence suggests that a fourth gene, CCM4, may also cause CCM, however it has yet to be identified.