A few studies have worked on providing details related to the outlook of disease progression. Two studies show that each year 0.5% of people who have never had bleeding from their brain cavernoma, but had symptoms of seizures, were affected by bleeding. In contrast, patients who have had bleeding from their brain cavernoma in the past had a higher risk of being affected by subsequent bleeding. The statistics for this are very broad, ranging from 4%-23% a year. Additional studies suggest that women and patients under the age of 40 are at higher risk of bleeding, but similar conducted studies did not reach the same conclusion. However, when cavernous hemangiomas are completely excised, there is very little risk of growth or rebleeding. In terms of life expectancy, not enough data has been collected on patients with this malformation in order to provide a representative statistical analysis.

The true incidence of cavernous hemangiomas is difficult to estimate because they are frequently misdiagnosed as other venous malformations. Cavernous hemangiomas of the brain and spinal cord (cerebral cavernous hemangiomas (malformations) (CCM)), can appear at all ages but usually occur in the third to fourth decade of a person's life with no sexual preference. In fact, CCM is present in 0.5% of the population. However, approximately 40% of those with malformations have symptoms. Asymptomatic individuals are usually individuals that developed the malformation sporadically, while symptomatic individuals usually have inherited the genetic mutation. The majority of diagnoses of CCM are in adults; however, 25% of cases of CCM are children. Approximately 5% of adults have liver hemangiomas in the United States, but most are asymptomatic. Liver hemangiomas usually occur between the ages of 30-50 and more commonly in women. Cases of infantile liver cavernomas are extremely rare. Cavernous hemangioma of the eye is more prevalent in women than men and between the ages of 20-40.

The incidence in the general population is roughly 0.5%, and clinical symptoms typically appear between 20 to 30 years of age. Once thought to be strictly congenital, these vascular lesions have been found to occur "de novo". It may appear either sporadically or exhibit autosomal dominant inheritance.

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.

The majority of patients with neurocutaneous melanosis are asymptomatic and therefore have a good prognosis with few complications. Most are not diagnosed, so definitive data in not available. For symptomatic patients, the prognosis is far worse. In patients without the presence of melanoma, more than 50% die within 3 years of displaying symptoms. While those with malignancy have a mortality rate of 77% with most patients displaying symptoms before the age of 2.

The presence of a Dandy-Walker malformation along with neurocutaneous melanosis, as occurs in 10% of symptomatic patients, further deteriorates prognosis. The median survival time for these patients is 6.5 months after becoming symptomatic.

The syndrome was first described in 1943 and believed to be associated with racemose hemangiomatosis of the retina and arteriovenous malformations of the brain. It is non-hereditary and belongs to phakomatoses that do not have a cutaneous (pertaining to the skin) involvement. This syndrome can affect the retina, brain, skin, bones, kidney, muscles, and the gastrointestinal tract.

Bonnet–Dechaume–Blanc syndrome results mainly from arteriovenous malformations. These malformations are addressed previously in the article, under “Signs and Symptoms.” Due to lack of research, it is difficult to provide a specific mechanism for this disorder. However, a number of examinations, mentioned under “Diagnosis,” can be performed on subjects to investigate the disorder and severity of the AVMs.

10-15% of intracranial AV malformations are DAVFs. There is a higher preponderance in females (61-66%), and typically patients are in their fourth or fifth generation of life. DAVFs are rarer in children.

Congenital hemangioma can be distinguished from infantile hemangioma because it is fully developed at birth. It forms during prenatal life and has reached its maximal size at birth. Congenital hemangioma can even be diagnosed in utero by prenatal ultrasound. Unlike IH, CH is more common in the extremities, has an equal sex distribution, and is solitary, with an average diameter of 5 cm. It commonly presents in the head and neck and in the lower extremities.

Congenital hemangioma are divided into 2 subgroups: the rapidly involuting congenital hemangiomas (RICHs) and the non-involuting congenital hemangiomas(NICHs).

The rapidly involuting congenital hemangioma, RICH, presents at birth as a solitary raised tumor with a central depression, scar, or ulceration surrounded by a rim of pallor. It is noted for its involution, which typically begins several weeks after birth and is completed no later than 14 months of age. After regression RICH may cause a residual deformity, such as atrophic skin and subcutaneous tissue. It mainly affects the limbs (52%), but also the head and neck region (42%) and the trunk (6%).

The non-involuting congenital hemangioma, NICH, presents as a solitary, well-circumscribed reddish-pink to purple plaque with central telangiectasia and hypopigmented rim. In contrast to RICH, NICH does not involute and rarely ulcerates. It persists into late childhood and can even mimic a vascular malformation by growing commensurately with the child. Although NICH can resemble RICH in its external appearance, it can be differentiated from RICH by a greater elevation and coarse telangiectases. It mainly affects the head and neck region (43%), but also the limbs (38%) and the trunk (19%).

Surgical resection for congenital hemangiomas is rarely needed, because RICH undergoes postnatal regression and NICH is benign and often asymptomatic. Resection may be indicated to improve the appearance of the affected area, as long as the surgical scar is less noticeable than the lesion. Other indications are problematic ulcers with persistent bleeding or chronic infection.

Although most NICH lesions are non-problematic and do not cause significant deformity, the threshold for resection of NICH is lower, because it neither involutes, nor responds to pharmacotherapy. RICH tumors are observed until involution is completed. Involuted RICH may leave behind atrophic tissue, which can be reconstructed with autologous grafts. It is often best to postpone excision until regression is complete.

There are effective pharmacologic treatments, which include intralesional corticosteroid injection, systemic corticosteroid injection, interferon α-2a or α-2b and angiogenic inhibitors. The use of corticosteroids leads to accelerated regression in 30%, stabilization of growth in 40%, lightening of color and softening of the tumor. However, 30% shows minimal or no response. Another drug treatment is interferon α-2a or α-2b. It is often used for patients who did not respond to corticosteroids. Although the response rate is much slower, it has been successful for 80% of children treated. The most serious side effect of interferon is a spastic diplegia. Other therapeutic options are embolization and pulsed-dye laser, which improves residual telangiectasias in RICH and in NICH.

A vascular anomaly is a kind of birthmark caused by a disorder of the vascular development, although it is not always present at birth. A vascular anomaly is a localized defect in blood vessels that can affect each part of the vasculature (capillaries, arteries, veins, lymphatics or a combination of these). These defects are characterized by an increased number of vessels and vessels that are both enlarged and sinuous. Some vascular anomalies are congenital and therefore present at birth, others appear within weeks to years after birth and others are acquired by trauma or during pregnancy. Inherited vascular anomalies are also described and often present with a number of lesions that increase with patients’ age. Vascular anomalies can also be a part of a syndrome and, occasionally, they can be acquired by trauma. The estimated prevalence of vascular anomalies is 4.5%. Vascular anomalies can occur throughout the whole body (skin, bone, liver, intestines, i.e.), but in 60% of patients vascular anomalies are localized in the head and neck region.

Vascular anomalies can present in various ways. Vascular anomalies that are situated deep below the skin, appear blue and are often called cavernous. Superficial vascular anomalies appear as red-coloured stains and are associated with vascular anomalies affecting the dermis. Historically, vascular anomalies have been labeled with descriptive terms, according to the food they resembled (port wine, strawberry, cherry, salmon patch). This imprecise terminology has caused diagnostic confusion, blocked communication and even caused incorrect treatment, as it does not differentiate between various vascular anomalies. However, in 1982, Mulliken introduced a classification that replaced these descriptive terms and gave direction to the management of various vascular anomalies. This classification, based on clinical features, natural history and cellular characteristics, divides vascular anomalies into two groups: vascular tumors and vascular malformations.

Although the appearance of both vascular tumors and vascular malformations can resemble, there are important differences between both.

Hemangioblastomas can cause polycythemia due to ectopic production of erythropoietin as a paraneoplastic syndrome.

Prognosis depends on the size and location of the tumour, untreated angiomatosis may lead to blindness and/ or permanent brain damage. Death may occur, with complications in the kidney or brain.

Once a patient with neurocutaneous melanosis becomes symptomatic, little can be done to improve prognosis as there is no effective treatment for the disorder. Most therapies are designed to treat the symptoms associated with the disorder, mainly those related to hydrocephalus. A ventriculoperitoneal shunt to relieve intracranial pressure is the preferred method.

Chemotherapy and radiotherapy have been shown to be ineffective in cases of neurocutaneous melanosis where malignancy is present. Additionally, due to the total infiltration of the central nervous system by these lesions, surgical resection is not a viable treatment option.

It has been demonstrated that early embryonic, post-zygotic somatic mutations in the NRAS gene are implicated in the pathogenesis of NCM. Recently, experimental treatment with MEK162, a MEK inhibitor, has been tried in a patient with NCM and progressive symptomatic leptomeningeal melanocytosis. Pathological studies with immunohistochemical and Western Blot analyses using Ki67 and pERK antibodies showed a potential effect of MEK inhibiting therapy. Further studies are needed to determine whether MEK inhibitors can effectively target NRAS-mutated symptomatic NCM.

Manual carotid self compression is a controversial treatment for DAVF. Patients using this method are told to compress the carotid with the opposite hand for approximately 10 minutes daily, and gradually increasing the frequency and duration of compression. Currently, it is unclear whether this method is an effective therapy.

The nature of this malformation remains unclear. Congenital, spontaneous, and acquired origins are accepted. The hypothesis of a spontaneous origin in the current case of SP is supported by no evidence of associated anomalies, such as cerebral aneurysmal venous malformations, systemic angiomas, venous angioma dural malformation, internal cerebral vein aneurysm, and cavernous hemangiomas.

Lymphangiomas are rare, accounting for 4% of all vascular tumors in children. Although lymphangioma can become evident at any age, 50% are seen at birth, and 90% of lymphangiomas are evident by 2 years of age.

There has been a great deal of research to understand the cause of PHACE Syndrome. The abnormalities associated with this syndrome are thought to be due to errors that occur very early during development. Unfortunately, why the errors occur, or the exact cause is still unknown. PHACE has a shared biology of other vascular anomalies. There may be a genetic component involved and studies are underway to investigate this idea. No familial cases have been identified to date. Research is ongoing to find the cause of all vascular anomalies including PHACE Syndrome.

Sinus pericranii is a venous anomaly where a communication between the intracranial dural sinuses and dilated epicranial venous structures exists. That venous anomaly is a collection of nonmuscular venous blood vessels adhering tightly to the outer surface of the skull and directly communicating with intracranial venous sinuses through diploic veins. The venous collections receive blood from and drain into the intracranial venous sinuses. The varicosities are intimately associated with the periostium, are distensible, and vary in size when changes in intracranial pressure occur.

They often appear in:

- Von Hippel-Lindau disease: It can be associated with Von Hippel-Lindau Disease and is a rare genetic multi system disorder characterized by the abnormal growth of tumours in the body. Symptoms may include headaches, problems with balance and walking, dizziness, weakness of the limbs, vision problems and high blood pressure.

- Bacillary angiomatosis

- Klippel-Trenaunay-Weber syndrome

- Sturge-Weber syndrome

The prognosis for lymphangioma circumscriptum and cavernous lymphangioma is generally excellent. This condition is associated with minor bleeding, recurrent cellulitis, and lymph fluid leakage. Two cases of lymphangiosarcoma arising from lymphangioma circumscriptum have been reported; however, in both of the patients, the preexisting lesion was exposed to extensive radiation therapy.

In cystic hygroma, large cysts can cause dysphagia, respiratory problems, and serious infection if they involve the neck. Patients with cystic hygroma should receive cytogenetic analysis to determine if they have chromosomal abnormalities, and parents should receive genetic counseling because this condition can recur in subsequent pregnancies.

Complications after surgical removal of cystic hygroma include damage to the structures in the neck, infection, and return of the cystic hygroma.

The outcome for hemangioblastoma is very good, if surgical extraction of the tumor can be achieved; excision is possible in most cases and permanent neurologic deficit is uncommon and can be avoided altogether if the tumor is diagnosed and treated early. Persons with VHL syndrome have a bleaker prognosis than those who have sporadic tumors since those with VHL syndrome usually have more than one lesion.

Many CNS cysts form in the womb during the first few weeks of development as a result of congenital defects. In adults cysts may also form due to a head injury or trauma, resulting in necrotic tissues (dead tissue), and can sometimes be associated with cancerous tumors or infection in the brain. However, the underlying reasons for cyst formation are still unknown.

Cavernous sinus thrombosis has a mortality rate of less than 20% in areas with access to antibiotics. Before antibiotics were available, the mortality was 80–100%. Morbidity rates also dropped from 70% to 22% due to earlier diagnosis and treatment.

Cysts derived from CNS tissues are very common in America. They are a subtype of cerebrovascular diseases, which are the third leading cause of death in America. Generally, CNS cysts are present in all geographic regions, races, ages, and sexes. However, certain types of CNS cysts are more prevalent in certain types of individuals than others. Some examples of incidence rates in specific types of cysts include:

- Arachnoid cysts are more prevalent in males than females

- Colloid cysts are more prevalent in adults

- Dermoid cysts are more prevalent in children under 10 years of age

- Epidermoid cysts are more prevalent in middle-aged adults

Various classifications have been proposed for CCF. They may be divided into low-flow or high-flow, traumatic or spontaneous and direct or indirect. The traumatic CCF typically occurs after a basal skull fracture. The spontaneous dural cavernous fistula which is more common usually results from a degenerative process in older patients with systemic hypertension

and atherosclerosis. Direct fistulas occur when the Internal Carotid artery (ICA) itself fistulizes into the Cavernous sinus whereas indirect is when a branch of the ICA or External Carotid artery (ECA) communicates with the cavernous sinus.

A popular classification divides CCF into four varieties depending on the type of arterial supply.