Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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September 12, 2019
Arterial displasia in PHACE SYNDROME
- Background
- PHACE syndrome is an acronym to describe a neurocutaneous syndrome encompassing the following features: posterior fossa brain malformations, segmental facial hemangiomas, arterial anomalies, cardiac anomalies, and eye abnormalities.
- When sternal clefting and/or supraumbilical raphe are also present, it is termed PHACES syndrome. The etiology is ambiguous, possibly representing a field defect due to an insult in early embryonic development.
- Clinical Presentation
- Most common sign is the presence of a large (>5cm)hemangioma on the child’s face, neck, or scalp.
- Patients diagnosed with PHACE have different combinations of abnormalities and symptoms. Patients are at risk for developmental delay, mental retardation, seizures, and infarcts, secondary to progressive vasculopathy.
- They can also present with hemiparesis/hypotonia, migraine headaches, cyclic vomiting syndrome, vision problems.
- Neurological deficits are not serious in most cases, but there is a higher risk of stroke in childhood.
- Key Diagnostic Features
- Imaging tests to be performed include a brain MRI, angiographic studies, and occasionally a cardiac MRI. The most frequently seen extracutaneous manifestations are CNS structural malformations and cerebrovascular anomalies and are ipsilateral to the facial hemangioma.
- Posterior fossa structural brain anomalies - Typical malformations include Dandy-Walker complex and cerebellar hemisphere hypoplasia ipsilateral to the hemangioma. Dandy-Walker malformation is characterized by the triad of hypoplasia of the vermis and cephalad rotation of the vermian remnant, cystic dilatation of the fourth ventricle extending posteriorly, enlarged posterior fossa with torcular-lambdoid inversion.
- Other less frequent findings include cortical dysplasia, dysplasia /agenesis of the corpus callosum, subcortical and subependymal gray matter heterotopias, and arachnoid cysts. Homogenosuly enhancing extraaxial lesions with T2 hyperintensity can also occur, consistent with intracranial hemangiomas.
- Segmental craniofacial hemangiomas - Hemangiomas tend to be large (>5 cm in diameter), can manifest as a solitary, confluent plaque or small individual papules clustered in a patterned distribution, covering a territory .
- Cerebrovascular arterial anomalies - Often involve the carotid or vertebrobasilar system.
- Dysplasia - most common (including ectasia, looping, kinking, and/or fusiform dilation).
- Narrowing (developmental hypoplasia or agenesis and acquired progressive stenosis or occlusion).
- Aberrant course or origin (in which arteries exhibit anomalous origin, elongation, or foreshortening).
- Persistence of embryonic anastomoses (typically, trigeminal, hypoglossal, and proatlantal arteries).
- Cardiac malformations - Coarctation of the aorta is the most common.
- Ocular abnormalities - Posterior segment anomalies such as persistent fetal vasculature, retinal vascular anomalies, morning glory anomaly, optic nerve hypoplasia, peripapilalry staphyloma, coloboma.
- Sternal defects or supraumbilical raphe.
- Differential Diagnosis
- Often misdiagnosed as cerebrofacial arteriovenous metameric syndrome including Wyburn-Mason syndrome and Sturge Weber syndrome. Both these conditions involve capillaries and veins; however, PHACES predominantly involves the arterial system.
- The hallmark of PHACES is a segmental hemangioma, usually facial.
- Wyburn-Mason syndrome - Characterized with unilateral vascular malformations that primarily involve the brain, orbits and facial structures.
- Sturge Weber syndrome - Characterized by facial port wine stains and pial angiomas. Other features include cortical, subcortical calcification, associated parenchymal volume loss, calvarial and regional sinus enlargement, enlargement of ipsilateral choroid plexus.
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