Vascular malformations refer to the localized collections of blood vessels that are not cancerous (nonneoplastic), abnormal in structure or number and lead to altered blood flow. While originally it was believed that the most vascular malformations are present at birth (congential), the lesions of cavernous malformation may develop throughout the lifetime of the affected individual. Other types of vascular malformations are not congential, but are caused by radiation, trauma or other injury to the spinal cord. The classifications of vascular malformations are done by size, location and type of change.
The four most common vascular malformations are capillary telangiectasias, cavernous malformations, venous malformations, and arteriovenous malformations.
Cavernous malformations are abnormal clusters of blood vessels that are characterized by multiple clusters of blood vessels with small bubbles or caverns through which the blood flows very slowly. Cavernous malformation vessels have a tendency to leak because of their thin wall. Due to this Leakage (bleeding) from these vascular lesions, the clinical symptoms associated with the illness appear. Though cavernous malformations are primarily found in the brain, sometimes they can be found on the skin, in the spinal cord, and in some rare cases in the retina as well.
Usually, cerebral cavernous malformations (CCMs) or cavernous malformations brain is found in the cortex or white matter of the brain. Unlike other lesions such as arteriovenous malformations, CCMs do not have brain tissue within the malformation. Also CCMs usually are not encapsulated. CCMs are changing in size, dynamic in structures, and number over time. The size of CCMs ranges from a few millimeters to several centimeters.
CCMs are found in up to 0.5% of the general population, and they constitute for a large proportion (8-15%) of all brain and spinal vascular malformations. The prevalence of people with at least one CCM lesion is high, while at least 40% of affected individuals may not have ever experienced symptoms of CCM or become diagnosed with cavernous malformation.