Cavernous hemangioma, also called cavernous angioma, venous malformation, or cavernoma, is a type of venous malformation due to endothelial dysmorphogenesis from a lesion which is present at birth. A cavernoma in the brain is called a cerebral cavernous malformation or CCM. Despite its designation as a hemangioma, a cavernous hemangioma is not a tumor as it does not display endothelial hyperplasia. The abnormal tissue causes a slowing of blood flow through the cavities, or "caverns". The blood vessels do not form the necessary junctions with surrounding cells, and the structural support from the smooth muscle is hindered, causing leakage into the surrounding tissue. It is the leakage of blood, referred to as hemorrhage, that causes a variety of symptoms known to be associated with the condition.
Symptoms
People with this condition in the brain may or may not experience symptoms. Some complications of the condition are life-threatening or cause major disruptions to normal functioning. Dangerous seizures due to compression of the brain, bleeding inside the brain tissue, vision problems, difficulty with speaking or using words, memory loss, ataxia, or hydrocephalus can occur. Less serious symptoms may include headaches and weakness or numbness in the arms or legs, though these symptoms alone do not indicate a person has the condition. In the eye, it may cause disruption or damage to the extraocular muscles and optic nerve which may manifest as double vision, progressive proptosis, decreased visual acuity, or other vision changes. It can lead to partial or complete blindness. When the condition occurs in the liver it usually does not cause symptoms, but some may experience pain in the upper right abdomen, a feeling of fullness after eating only a small amount of food, decreased appetite, nausea, or vomiting.
Presentation
Cavernous hemangiomas can arise nearly anywhere in the body where there are blood vessels. They are sometimes described as resembling raspberries because of the appearance of bubble-like caverns. Unlike capillary hemangiomas, cavernous ones can be life-threatening and do not regress.
Causes
Most cases of cavernomas are thought to be congenital; however they can develop over the course of a lifetime. While there is no definitive cause, research suggests that genetic mutations result in the condition. Congenital hemangiomas that appear on the skin are known as either vascular or red birthmarks.
Familial cerebral cavernous malformations are known to occur. The mutations may be inherited in an autosomal dominant fashion or occur sporadically. Overall, familial disease is thought to be responsible for one-third to one-half of cases. In the US, approximately 50% of Hispanic patients with cerebral cavernous malformations have a familial form. In contrast, the familiar form of the condition accounts for only 10 to 20% of cases in Caucasians. The reason for this difference is not presently known.
Several genes – K-Rev interaction trapped 1 (ССМ1), Malcavernin (CCM2) and Programmed cell death protein 10 (ССМ3) – have been identified as having mutations thought to be related to these lesions. These genes are located at 7q21.2 (chromosome 7 long arm), 7p13 (chromosome 7 short arm) and 3q25.2-q27 (chromosome 3 long arm) respectively. These lesions are further discussed in the Online Mendelian Inheritance in Man site – the reference numbers are OMIM 116860, OMIM 603284 and OMIM 603285 respectively.
Variations
Cerebral cavernomas
Cavernous hemangiomas located in the brain or spinal cord are referred to as cerebral cavernomas or more usually as cerebral cavernous malformations (CCMs), and can be found in the white matter, but often abut the cerebral cortex. When they contact the cortex, they can represent a potential seizure focus for the patient. Unlike other cavernous hemangiomas, there is no tissue within the malformation and its borders are not encapsulated. Therefore, they can change in size and number over time.
Liver cavernous hemangioma
Cavernous hemangiomas are erroneously called the most common benign tumors of the liver. Usually one malformation 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. These lesions are better classified as venous malformations.