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.

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.

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.

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.

Angiomatosis is a non-neoplastic condition characterised by nests of proliferating capillaries arranged in a lobular pattern, displacing adjacent muscle and fat. It consists of many angiomas.

These tend to be cavernous hemangiomas, which are sharply defined, sponge-like tumors composed of large, dilated, cavernous vascular spaces.

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.

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.

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 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.

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.

Cavernous venous malformations present as rounded, bright red or deep purple, spongy nodules, occurring chiefly on the head and neck and may involve both the skin and the mucous membranes.

It can be associated with "KRIT1", "CCM2" or "PDCD10".

Most juvenile polyps are benign, however, malignancy can occur. The cumulative lifetime risk of colorectal cancer is 39% in patients with juvenile polyposis syndrome.

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.

Diet and lifestyle are believed to play a large role in whether colorectal polyps form. Studies show there to be a protective link between consumption of cooked green vegetables, brown rice, legumes, and dried fruit and decreased incidence of colorectal polyps.

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.

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.

Mortality is indirect and caused by complications. After cholangitis occurs, patients typically die within 5–10 years.

Juvenile Polyposis Syndrome can occur sporadically in families or be inherited in an autosomal dominant manner.

Two genes associated with Juvenile Polyposis Syndrome are BMPR1A and SMAD4. Gene testing may be useful when trying to ascertain which non-symptomatic family members may be at risk of developing polyps, however having a known familial mutation would be unlikely to change the course of treatment. A known mutation may also be of use for affected individuals when they decide to start a family as it allows them reproductive choices.

While mutations in the gene PTEN were also thought to have caused Juvenile Polyposis Syndrome, it is now thought that mutations in this gene cause a similar clinical picture to Juvenile Polyposis Syndrome but are actually affected with Cowden syndrome or other phenotypes of the PTEN hamartoma tumor syndrome.

Caroli disease is typically found in Asia, and diagnosed in persons under the age of 22. Cases have also been found in infants and adults. As medical imaging technology improves, diagnostic age decreases.

The incidence of the mutation is between 1 in 10,000 and 1 in 15,000 births.

By age 35 years, 95% of individuals with FAP (>100 adenomas) have polyps. Without colectomy, colon cancer is virtually inevitable. The mean age of colon cancer in untreated individuals is 39 years (range 34–43 years).

Attentuated FAP arises when APC is defective but still somewhat functional. As a result, it retains part of its ability to suppress polyps. Therefore, attenuated FAP manifests as colorectal cancer unusually late (age 40–70, average=55), and typically with few, or at least far fewer polyps (typically 30), than the more usual version of FAP, at an age when FAP is no longer considered much of a likelihood or risk according to usual FAP epidemiology.

Treatment for a nasal septal abscess is similar to that of other bacterial infections. Aggressive broad spectrum antibiotics may be used after the infected area has been drained of fluids.

Many causes exist including:

- diverticulitis : most common ~ 60%

- colorectal cancer (CRC) : ~ 20%

- Crohn's disease : ~ 10%

- radiotherapy

- appendicitis

- trauma

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.

Colorectal polyps can be detected using a faecal occult blood test, flexible sigmoidoscopy, colonoscopy, virtual colonoscopy, digital rectal examination, barium enema or a pill camera.

Malignant potential is associated with

- degree of dysplasia

- Type of polyp (e.g. villous adenoma):

- Tubular Adenoma: 5% risk of cancer

- Tubulovillous adenoma: 20% risk of cancer

- Villous adenoma: 40% risk of cancer

- Size of polyp:

- <1 cm =<1% risk of cancer

- 1 cm=10% risk of cancer

- 2 cm=15% risk of cancer

Normally an adenoma which is greater than 0.5 cm is treated