Cavernous hemangiomas are the most common benign tumors of the liver. Usually one tumor exists, but multiple lesions can occur in the left or right lobe of the liver in 40% of patients. Their sizes can range from a few millimeters to 20 centimetres. Those over 5 cm are often referred to as "giant hemangiomas".

In the eye, it is known as orbital cavernous hemangioma and is found in women more frequently than men, most commonly between the ages of 20-40. This neoplasm is usually located within the muscle cone, which is lateral to the optic nerve. It is not usually treated unless the patient is symptomatic. Visual impairment happens when the optic nerve is compressed or the extraocular muscles are surrounded.

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.

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.

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.

It is a vascular malformation wherein blood vessels proliferate along with accompanying mature fat and fibrous tissue, lymphatics and sometimes nerves. They may involve skin, subcutaneous tissue, skeletal muscle and occasionally bone.

Sinus pericranii typically present as soft palpable masses along midline skull, which may fluctuate in size depending on body positioning. Classically, these lesions are not associated with color change of the overlying skin, such as with other vascular lesions such as hemangioma.

The most common signs/symptoms of DAVFs are:

1. Pulsatile tinnitus

2. Occipital bruit

3. Headache

4. Visual impairment

5. Papilledema

Pulsatile tinnitus is the most common symptom in patients, and it is associated with transverse-sigmoid sinus DAVFs. Carotid-cavernous DAVFs, on the other hand, are more closely associated with pulsatile exophthalmos. DAVFs may also be asymptomatic (e.g. cavernous sinus DAVFs).

Clinical manifestations of intraparenchymal hemorrhage are determined by the size and location of hemorrhage, but may include the following:

- Hypertension, fever, or cardiac arrhythmias

- Nuchal rigidity

- Subhyaloid retinal hemorrhages

- Altered level of consciousness

- Anisocoria, Nystagmus

- Focal neurological deficits

- Putamen - Contralateral hemiparesis, contralateral sensory loss, contralateral conjugate gaze paresis, homonymous hemianopsia, aphasia, neglect, or apraxia

- Thalamus - Contralateral sensory loss, contralateral hemiparesis, gaze paresis, homonymous hemianopia, miosis, aphasia, or confusion

- Lobar - Contralateral hemiparesis or sensory loss, contralateral conjugate gaze paresis, homonymous hemianopia, abulia, aphasia, neglect, or apraxia

- Caudate nucleus - Contralateral hemiparesis, contralateral conjugate gaze paresis, or confusion

- Brain stem - Tetraparesis, facial weakness, decreased level of consciousness, gaze paresis, ocular bobbing, miosis, or autonomic instability

- Cerebellum - Ataxia, usually beginning in the trunk, ipsilateral facial weakness, ipsilateral sensory loss, gaze paresis, skew deviation, miosis, or decreased level of consciousness

Sinus pericranii (SP) is a rare disorder characterized by a congenital (or occasionally, acquired) epicranial venous malformation of the scalp. Sinus pericranii is an abnormal communication between the intracranial and extracranial venous drainage pathways. Treatment of this condition has mainly been recommended for aesthetic reasons and prevention of hemorrhage.

Most commonly found adjacent to dural sinuses in the following locations:

1. Transverse (lateral) sinus, left-sided slightly more common than right

2. Intratentorial

3. From the posterior cavernous sinus, usually draining to the transverse or sigmoid sinuses

4. Vertebral artery (posterior meningeal branch)

A developmental venous anomaly (DVA, formerly known as venous angioma) is a congenital variant of the cerebral venous drainage. On imaging it is seen as a number of small deep parenchymal veins converging toward a larger collecting vein.

In younger patients, vascular malformations, specifically AVMs and cavernous angiomas are more common causes for hemorrhage. In addition, venous malformations are associated with hemorrhage.

In the elderly population, amyloid angiopathy is associated with cerebral infarcts as well as hemorrhage in superficial locations, rather than deep white matter or basal ganglia. These are usually described as "lobar". These bleedings are not associated with systemic amyloidosis.

Hemorrhagic neoplasms are more complex, heterogeneous bleeds often with associated edema. These hemorrhages are related to tumor necrosis, vascular invasion and neovascularity. Glioblastomas are the most common primary malignancies to hemorrhage while thyroid, renal cell carcinoma, melanoma, and lung cancer are the most common causes of hemorrhage from metastatic disease.

Other causes of intraparenchymal hemorrhage include hemorrhagic transformation of infarction which is usually in a classic vascular distribution and is seen in approximately 24 to 48 hours following the ischemic event. This hemorrhage rarely extends into the ventricular system.

There are three distinct types of lymphangioma, each with their own symptoms. They are distinguished by the depth and the size of abnormal lymph vessels, but all involve a malformation of the lymphic system. Lymphangioma circumscriptum can be found on the skin's surface, and the other two types of lymphangiomas occur deeper under the skin.

- Lymphangioma circumscriptum, a microcystic lymphatic malformation, resembles clusters of small blisters ranging in color from pink to dark red. They are benign and do not require medical treatment, although some patients may choose to have them surgically removed for cosmetic reasons.

- Cavernous lymphangiomas are generally present at birth, but may appear later in the child's life. These bulging masses occur deep under the skin, typically on the neck, tongue and lips, and vary widely in size, ranging from as small as a centimeter in diameter to several centimeters wide. In some cases, they may affect an entire extremity such as a hand or foot. Although they are usually painless, the patient may feel mild pain when pressure is exerted on the area. They come in the colors white, pink, red, blue, purple, and black; and the pain lessens the lighter the color of the bump.

- Cystic hygroma shares many commonalities with cavernous lymphangiomas, and some doctors consider them to be too similar to merit separate categories. However, cystic lymphangiomas usually have a softer consistency than cavernous lymphangiomas, and this term is typically the one that is applied to lymphangiomas that develop in fetuses. They usually appear on the neck (75%), arm pit or groin areas. They often look like swollen bulges underneath the skin.

DVA can be characterized by the Caput medusae sign of veins, which drains into a larger vein. The drains will either drain into a Dural venous sinuses or into a deep ependymal vein. It appears to look like a Palm tree.

Lymphangiomas have traditionally been classified into three subtypes: "capillary" and "cavernous lymphangiomas" and cystic hygroma. This classification is based on their microscopic characteristics. A fourth subtype, the "hemangiolymphangioma" is also recognized.

- Capillary lymphangiomas

- Cavernous lymphangiomas

- Cystic hygromas

- Hemangiolymphangioma

Lymphangiomas may also be classified into "microcystic", "macrocystic", and "mixed" subtypes, according to the size of their cysts.

- Microcystic lymphangiomas

- Macrocystic lymphangiomas

- Mixed lymphangiomas

Finally, lymphangiomas may be described in stages, which vary by location and extent of disease. In particular, stage depends on whether lymphangiomas are present above or "superior" to the hyoid bone ("suprahyoid"), below or "inferior" to the hyoid bone ("infrahyoid"), and whether the lymphangiomas are on one side of the body ("unilateral") or both ("bilateral").

- Stage I: Unilateral infrahyoid.

- Stage II: Unilateral suprahyoid.

- Stage III: Unilateral suprahyoid and infrahyoid.

- Stage IV: Bilateral suprahyoid.

- Stage V: Bilateral suprahyoid and infrahyoid.

The disease is present at birth, but clinical manifestations are often not seen until later in life. Patients typically experience the sudden onset of pain, numbness, or weakness in their extremities as children or young adults. These symptoms may remit or remain stable and often can be localized below a specific dermatome. Symptoms tend to worsen over time either by discrete steps or continuously. Early development of weakness may portend a more aggressive course. Less commonly, weakness or bowel and bladder dysfunction may be presenting symptoms.

The major debility from Cobb syndrome is the onset of weakness, paresis, sensory loss, and loss of bowel and bladder control. A possible complication if treatment is delayed is Foix-Alajouanine disease or subacute necrotic myelopathy due to thrombosis in the spinal angioma.

Cutaneous lesions may be distributed anywhere in the dermatome, from midline back to abdomen. Midline back lesions may be associated with spina bifida. The cutaneous lesion may be very faint and may be more pronounced when the patient performs a Valsalva maneuver which increases abdominal pressure and causes preferential filling of the cutaneous angioma. Neurological examination will reveal weakness or paralysis and numbness or decreased sensation with a sharp upper cutoff.

CCF symptoms include bruit (a humming sound within the skull due to high blood flow through the arteriovenous fistula), progressive visual loss, and pulsatile proptosis or progressive bulging of the eye due to dilatation of the veins draining the eye. Pain is the symptom that patients often find the most difficult to tolerate.

Patients usually present with sudden or insidious onset of redness in one eye, associated with progressive proptosis or bulging.

They may have a history of similar episodes in the past.

A cavernous liver haemangioma or hepatic haemangioma is a benign tumour of the liver composed of hepatic endothelial cells. It is the most common liver tumour, and is usually asymptomatic and diagnosed incidentally on radiological imaging. Liver haemangiomas are thought to be congenital in origin. Several subtypes exist, including the giant hepatic haemangioma, which can cause significant complications.

This large, atypical haemangioma of the liver may present with abdominal pain or fullness due to haemorrhage, thrombosis or mass effect. It may also lead to left ventricular volume overload and heart failure due to the increase in cardiac output which it causes. Further complications are Kasabach-Merritt syndrome, a form of consumptive coagulopathy due to thrombocytopaenia, and rupture.

Carotid cavernous fistulae may form following closed or penetrating head trauma, surgical damage, rupture of an intracavernous aneurysm, or in association with connective tissue disorders, vascular diseases and dural fistulas.

Sturge–Weber syndrome is usually manifested at birth by a port-wine stain on the forehead and upper eyelid of one side of the face, or the whole face. The birthmark can vary in color from light pink to deep purple and is caused by an overabundance of capillaries around the ophthalmic branch of the trigeminal nerve, just under the surface of the face. There is also malformation of blood vessels in the pia mater overlying the brain on the same side of the head as the birthmark. This causes calcification of tissue and loss of nerve cells in the cerebral cortex.

Neurological symptoms include seizures that begin in infancy and may worsen with age. Convulsions usually happen on the side of the body opposite the birthmark which vary in severity. There may also be muscle weakness on the side of the body opposite the birthmark.

Some children will have developmental delays and cognitive delays; about 50% will have glaucoma (optic neuropathy often associated with increased intraocular pressure), which can be present at birth or develop later. Glaucoma can be expressed as leukocoria, which should include also further evaluation for retinoblastoma. Increased pressure within the eye can cause the eyeball to enlarge and bulge out of its socket (buphthalmos).

Sturge–Weber syndrome rarely affects other body organs.

LCAs most often are not clinically detectable. On occasion, their first presentation may be with splenic rupture.

Most patients show no symptoms and the tumours are found incidentally.

Cobb syndrome is a rare congenital disorder characterized by visible skin lesions with underlying spinal angiomas or arteriovenous malformations (AVMs). The skin lesions of Cobb syndrome typically are present as port wine stains or angiomas, but reports exist of angiokeratomas, angiolipomas, and lymphangioma circumscriptum. The intraspinal lesions may be angiomas or AVMs and occur at levels of the spinal cord corresponding to the affected skin dermatomes. They may in turn produce spinal cord dysfunction and weakness or paralysis.

The disorder was first described by Berenbruch in 1890, but became widely known only after Cobb's report in 1915. Cobb syndrome is thought to be more common in males and have no racial predilection, but only a few dozen cases are known. It is believed to be due to a sporadic mutation, since parents of affected children usually have no evidence of the disease.

A tufted angioma (also known as an "Acquired tufted angioma," "Angioblastoma," "Angioblastoma of Nakagawa," "Hypertrophic hemangioma," "Progressive capillary hemangioma," and "Tufted hemangioma") usually develops in infancy or early childhood on the neck and upper trunk, and is an ill-defined, dull red macule with a mottled appearance, varying from 2 to 5 cm in diameter.