If the medical history and the actual exam of the hemangioma look typical for PHACE Syndrome, more tests are ordered to confirm the diagnosis. These tests may include:

- Ultrasound

- Magnetic resonance imaging (MRI)

- Magnetic resonance angiography of the brain (MRA)

- Echocardiogram

- Eye exam by an eye doctor

- Other tests may be needed for diagnosis and treatment

Diagnosis is generally made by magnetic resonance imaging (MRI), particularly using a specific imaging technique known as a gradient-echo sequence MRI, which can unmask small or punctate lesions that may otherwise remain undetected. These lesions are also more conspicuous on FLAIR imaging compared to standard T2 weighing. FLAIR imaging is different from gradient sequences. Rather, it is similar to T2 weighing but suppresses free-flowing fluid signal. Sometimes quiescent CCMs can be revealed as incidental findings during MRI exams ordered for other reasons. Many cavernous hemangiomas are detected "accidentally" during MRIs searching for other pathologies. These "incidentalomas" are generally asymptomatic. In the case of hemorrhage, however, a CT scan is more efficient at showing new blood than an MRI, and when brain hemorrhage is suspected, a CT scan may be ordered first, followed by an MRI to confirm the type of lesion that has bled.

Sometimes the lesion appearance imaged by MRI remains inconclusive. Consequently neurosurgeons will order a cerebral angiogram or magnetic resonance angiogram (MRA). Since CCMs are low flow lesions (they are hooked into the venous side of the circulatory system), they will be angiographically occult (invisible). If a lesion is discernible via angiogram in the same location as in the MRI, then an arteriovenous malformation (AVM) becomes the primary concern.

Some patients have a few or no histopathologic abnormalities. Histological examination of a biopsy may show an increase in the number and size of capillaries and veins (rarely lymphatics), dilated capillaries located in the deeper dermis, and hyperplasia and swollen endothelial cells with occasional dilated veins and venous lakes.

Amniotic band syndrome is considered an accidental event and it does not appear to be genetic or hereditary, so the likelihood of it occurring in another pregnancy is remote. The cause of amnion tearing is unknown and as such there are no known preventative measures.

Amniotic band syndrome is often difficult to detect before birth as the individual strands are small and hard to see on ultrasound. Often the bands are detected indirectly because of the constrictions and swelling upon limbs, digits, etc. Misdiagnosis is also common, so if there are any signs of amniotic bands, further detailed ultrasound tests should be done to assess the severity. 3D ultrasound and MRI can be used for more detailed and accurate diagnosis of bands and the resulting damage/danger to the fetus.

The diagnosis of AOS is a clinical diagnosis based on the specific features described above. A system of major and minor criteria was proposed.

The combination of two major criteria would be sufficient for the diagnosis of AOS, while a combination of one major and one minor feature would be suggestive of AOS. Genetic testing can be performed to test for the presence of mutation in one of the known genes, but these so far only account for an estimated 50% of patients with AOS. A definitive diagnosis may therefore not be achieved in all cases.

Surgical correction is recommended when a constriction ring results in a limb contour deformity, with or without lymphedema.

The surgical treatment involves the resection of the extracranial venous package and ligation of the emissary communicating vein. In some cases of SP, surgical excision is performed for cosmetic reasons. The endovascular technique has been described by transvenous approach combined with direct puncture and the recently endovascular embolization with Onyx.

In general, there is no treatment available for CMTC, although associated abnormalities can be treated. In the case of limb asymmetry, when no functional problems are noted, treatment is not warranted, except for an elevation device for the shorter leg.

Laser therapy has not been successful in the treatment of CMTC, possibly due to the presence of many large and deep capillaries and dilated veins. Pulsed-dye laser and long-pulsed-dye laser have not yet been evaluated in CMTC, but neither argon laser therapy nor YAG laser therapy has been helpful.

When ulcers develop secondary to the congenital disease, antibiotic treatment such as oxacillin and gentamicin administered for 10 days has been prescribed. In one study, the wound grew Escherichia coli while blood cultures were negative.

The overall prognosis is excellent in most cases. Most children with Adams–Oliver syndrome can likely expect to have a normal life span. However, individuals with more severe scalp and cranial defects may experience complications such as hemorrhage and meningitis, leading to long-term disability.

It can be diagnosed with CT scan, angiography, transesophageal echocardiography, or cardiac MRI. Unfortunately, less invasive and expensive testing, such as transthoracic echocardiography and CT scanning are generally less sensitive.

Hepatic microvascular dysplasia (HMD or MVD) or portal atresia is a disorder where mixing of venous blood and arterial blood in the liver occurs at the microscopic level. It occurs most commonly in certain dog breeds such as the Cairn and Yorkshire terriers although any dog breed may be at risk.

This disease may also be found in cats.

HMD is sometimes misdiagnosed as Portosystemic vascular anomaly (PSVA) or a "Liver Shunt" (portosystemic shunt). HMD can be diagnosed with an MRI, using a tracing dye in the subject's blood, and observing the flow of blood through the subject's liver and surrounding areas (stomach, intestine) for anomalies. It can also be diagnosed using a bile-acid level test; or more accurately, a "fasting-blood ammonia levels" test. Symptoms include stunted growth in the first 6–9 months, vomiting, seizures, and hydro-encephalitic episodes (from ammonia concentrating in the blood). HMD is usually treated non-surgically with antibiotics (metronidazole) and stool-softeners (lactulose).

The reported incidence of constriction ring syndrome varies from 1/1200 and 1/15000 live births. The prevalence is equally in male and female.

Fetomaternal factors like prematurity, maternal illnes, low birth weight and maternal drug exposure are predisposing factors for the constriction ring syndrome.

No positive relationship between CRS and genetic inheritance has been reported.

Usually the hemangioma requires medical therapy. The child may need other therapies, depending on what other organs or structures are involved.

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.

There is no known cure for this syndrome. Patients usually need ophthalmic surgery and may also need dental surgery

Genetic counseling and screening of the mother's relatives is recommended.

A "Partial anomalous pulmonary venous connection" (or "Partial anomalous pulmonary venous drainage" or "Partial anomalous pulmonary venous return") is a congenital defect where the left atrium is the point of return for the blood from some (but not all) of the pulmonary veins.

It is less severe than total anomalous pulmonary venous connection which is a life-threatening anomaly requiring emergent surgical correction, usually diagnosed in the first few days of life. Partial anomalous venous connection may be diagnosed at any time from birth to old age. The severity of symptoms, and thus the likelihood of diagnosis, varies significantly depending on the amount of blood flow through the anomalous connections. In less severe cases, with smaller amounts of blood flow, diagnosis may be delayed until adulthood, when it can be confused with other causes of pulmonary hypertension. There is also evidence that a significant number of mild cases are never diagnosed, or diagnosed incidentally. It is associated with other vascular anomalies, and some genetic syndromes such as Turner syndrome.

Figueroa and Pruzanksky classified HFM patients into three different types:

- Type I : Mild hypoplasia of the ramus , and the body of the mandible is slightly affected.

- Type II : The condyle and ramus are small, the head of the condyle is flattened , the glenoid fossa is absent , the condyle is hinged on a flat, often convex, infratemporal surface , the coronoid may be absent.

- Type III: The ramus is reduced to a thin lamina of bone or is completely absent. There is no evidence of a TMJ.

At present, treatment for tetrasomy 18p is symptomatic, meaning that the focus is on treating the signs and symptoms of the conditions as they arise. The Chromosome 18 Clinical Research Center has published a list of recommended screening and evaluations:

Suspicion of a chromosome abnormality is typically raised due to the presence of developmental delays or congenital malformations. Diagnosis of tetrasomy 18p is typically made via a routine chromosome analysis from a blood sample. The diagnosis can also be made prenatally by chorionic villus sampling or amniocentesis.

Severity of tetrasomy 18p is variable. Individuals with mosaicism are typically less severely affected than non-mosaic individuals.

In 1983 Heffez and colleagues published a case report in which they suggested eight criteria for a definitive diagnosis of Gorham's disease:

- Positive biopsy with the presence of angiomatous tissue

- Absence of cellular atypia

- Minimal or no osteoblastic response or dystrophic calcifications

- Evidence of local bone progressive osseous resorption

- Non-expansile, non-ulcerative lesions

- No involvement of viscera

- Osteolytic radiographic pattern

- Negative hereditary, metabolic, neoplastic, immunologic, or infectious etiology.

In the early stages of the disease x-rays reveal changes resembling patchy osteoporosis. As the disease progresses bone deformity occurs with further loss of bone mass and, in the tubular bones (the long bones of the arms and legs), a concentric shrinkage is often seen which has been described as having a "sucked candy" appearance. Once the cortex (the outer shell) of the bone has been disrupted, vascular channels may invade adjacent soft tissues and joints. Eventually, complete or near-complete resorption of the bone occurs and may extend to adjacent bones, though spontaneous arrest of bone loss has been reported on occasion. Throughout this process, as the bone is destroyed it is replaced by angiomatous and/or fibrous tissue.

Often Gorham's disease is not recognized until a fracture occurs, with subsequent improper bone healing. The diagnosis essentially is one of exclusion and must be based on combined clinical, radiological, and histopathological findings. X-rays, CT scans, MRIs, ultrasounds, and nuclear medicine (bone scans) are all important tools in the diagnostic workup and surgical planning, but none have the ability alone to produce a definitive diagnosis. Surgical biopsy with histological identification of the vascular or lymphatic proliferation within a generous section of the affected bone is an essential component in the diagnostic process.

Recognition of the disease requires a high index of suspicion and an extensive workup. Because of its serious morbidity, Gorham's must always be considered in the differential diagnosis of osteolytic lesions.

The diagnosis of IP is established by clinical findings and occasionally by corroborative skin biopsy. Molecular genetic testing of the NEMO IKBKG gene (chromosomal locus Xq28) reveals disease-causing mutations in about 80% of probands. Such testing is available clinically.

In addition, females with IP have skewed X-chromosome inactivation; testing for this can be used to support the diagnosis.

Many people in the past were misdiagnosed with a second type of IP, formerly known as IP1. This has now been given its own name - 'Hypomelanosis of Ito' (incontinentia pigmenti achromians). This has a slightly different presentation: swirls or streaks of hypopigmentation and depigmentation. It is "not" inherited and does not involve skin stages 1 or 2. Some 33–50% of patients have multisystem involvement — eye, skeletal, and neurological abnormalities. Its chromosomal locus is at Xp11, rather than Xq28.

Kaposiform hemangioendothelioma (KHE) is a rare vascular neoplasm that is locally aggressive but without metastatic potential. It occurs particularly in the skin, deep soft tissue, retroperitoneum, mediastinum, and rarely in bone. Although lesions occur solitary, they often involve large areas of the body, such as the head/neck region (40%), trunk (30%), or extremity (30%).

Usually, it is present at birth as a flat, reddish-purple, tense and edematous lesion.

Although half of lesions are congenital, 58% of KHE develop during infancy, 32% between age 1 and 10 years (32%) and 10% after 11 years of age. Moreover, adult onset has been described too with mainly males being affected. Both sexes are affected equally in children.

Lesions are often greater than 5 cm in diameter and can cause visible deformity and pain. During early childhood, KHE may enlarge and after 2 years of age, it may partially regress. Though, it usually persists longterm. In addition, 50% of patients suffer from coagulopathy due to thrombocytopenia (<25,000/mm3), presenting with petechiae and bleeding. This is called the Kasabach-Merritt Phenomenon, which is caused by trapping of platelets and other clotting factors within the tumor. Kasabach-Merritt Phenomenon is less likely in patients with lesions less than 8 cm. As two-thirds of adult-onset KHE tumors are less than 2 cm, KHE in adults is rarely associated with Kasabach-Merritt Phenomenon.

Patients with KHE and Kasabach-Merritt Phenomenon present with petechiae and ecchymosis.

Most KHE tumors are diffuse involving multiple tissue planes and important structures. Resection of KHE is thus often difficult. Treatment of kaposiform hemangioendothelioma is therefore medical. The primary drug is interferon alfa, which is successful in 50% of children. Another option is vincristine, which has lots of side-effects, but has a response rate of 90%. Drug therapy is often used in shrinking the tumor and treating the coagulopathy. However, many of these kaposiform hemangioendotheliomas do not completely regress and remain as a much smaller asymptomatic tumor. However, KHE still has a high mortality rate of 30%. Although complete surgical removal with a large margin has the best reported outcome, it is usually not done because of the risk of bleeding, extensiveness, and the anatomic site of the lesion.

Operative management may be possible for small or localized lesions. Removal of larger areas also may be indicated for symptomatic patients or for patients who have failed farmacotherapy. Resection is not required for lesions that are not causing functional problems, because KHE is benign and because resection could cause deformity.

Treatment of Gorham's disease is for the most part palliative and limited to symptom management.

Sometimes the bone destruction spontaneously ceases and no treatment is required. But when the disease is progressive, aggressive intervention may be necessary. Duffy and colleagues reported that around 17% of patients with Gorham's disease in the ribs, shoulder, or upper spine experience extension of the disease into the chest, leading to chylothorax with its serious consequences, and that the mortality rate in this group can reach as high as 64% without surgical intervention.

A search of the medical literature reveals multiple case reports of interventions with varying rates of success as follows:

Cardiothoracic (heart & lung):

- Pleurodesis

- Ligation of thoracic duct

- Pleurperitoneal shunt

- Radiation therapy

- Pleurectomy

- Surgical resection

- Thalidomide

- Interferon alpha-2b

- TPN (total parenteral nutrition)

- Thoracentesis

- Diet rich in medium-chain triglycerides and protein

- Chemotherapy

- Sclerotherapy

- Transplantation

Skeletal:

- Interferon alpha-2b

- Bisphosphonate (e.g. pamidronate)

- Surgical resection

- Radiation therapy

- Sclerotherapy

- Percutaneous bone cement

- Bone graft

- Prosthesis

- Surgical stabilization

- Amputation

To date, there are no known interventions that are consistently effective for Gorham's and all reported interventions are considered experimental treatments, though many are routine for other conditions. Some patients may require a combination of these approaches. Unfortunately, some patients will not respond to any intervention.

Patients with abnormal cardiac and kidney function may be more at risk for hemolytic uremic syndrome