Moyamoya Vasculopathy in PHACE Syndrome: Six New Cases and Review of the Literature

Long-term clinical and radiological trajectories of craniocervical vasculopathy in children with PHACE syndrome

AIM

To describe the rates of stroke and craniocervical vasculopathy progression in children with posterior fossa malformations, hemangioma, arterial anomalies, coarctation of the aorta/cardiac defects, and eye abnormalities (PHACE) syndrome.

METHOD

A single-center, retrospective natural history study of children with PHACE syndrome. Clinical and sequential neuroimaging data were reviewed to study the characteristics and progression of vasculopathy and calculate the rates of arterial ischemic stroke (AIS) and transient ischemic stroke (TIA). Vasculopathy progression was defined as worsening or new vascular findings on follow-up magnetic resonance angiography.

RESULTS

Thirty-four children with cerebrovascular abnormalities at the PHACE syndrome diagnosis were studied (age range = 2 to 18 years, 85% females). Median age at the initial diagnosis was 5.5 months (interquartile range = 1-52 months); median age at the last follow-up was 8 years 6 months (range = 2-18 years). Overall, 10 (29%) patients had radiological progression of their vasculopathy, with a cumulative progression-free rate of 73% (95% confidence interval [CI] = 0.57-0.89), and a cumulative TIA-free and AIS-free rate of 87% (95% CI = 0.745-0.99). Vasculopathy was continuously progressive in six patients (18%) at the last follow-up. Three patients (9%) had TIA and all had progressive vasculopathy. One patient had presumed perinatal AIS at the initial PHACE diagnosis, while no other patient experienced an AIS during the follow-up.

INTERPRETATION

In children with PHACE syndrome, craniocervical vasculopathy is non-progressive and asymptomatic in the majority of cases. The risk of ischemic stroke in these children is very low. Larger and prospective studies are necessary to confirm these findings.

"Face(s)" of a PHACE(S) Syndrome Patient before and after Therapy: Particular Case Report and Review of Literature

A rare, uncommon disorder called PHACE(S) (P-posterior fossa anomalies, H-hemangioma, A-arterial anomalies, C-cardiac anomalies, E-eye anomalies, and S-sternal cleft) of unknown etiology was rarely reported. Children are susceptible to developing PHACE(S) syndrome from the moment they are born. It may be challenging for a physician to appropriately diagnose and treat children with PHACE due to the multifaceted nature of the disease and the extensive range of consequences that may be associated with it. A one-month-old newborn girl was admitted to hospital with extensive, multiple facial infantile hemangiomas, ulceration of the lower lip hemangioma-like lesion, cardiovascular, sternal, and neurological concomitant malformations. Five days following the initial application of the medication, systemic treatment with propranolol and topical treatment with silver sulfadiazine produced their first noticeable benefits. The lip ulceration was mostly healed and facial hemangioma started to regress. The regression continued under therapy and this effect persists for 6 months since Propranolol therapy ended. No cardiovascular or neurological clinical events have been registered during follow-up. The present case has three peculiarities: (1) high number of facial hemangiomas; (2) presence of subependymal cyst not yet reported in the literature associated with PHACE syndrome; and (3) lack of cardiovascular events during therapy knowing that these events frequently appear in PHACE syndrome patients.

Alström's Syndrome: Neurological Manifestations and Genetics

Alström syndrome (ALMS) is a rare ciliopathy with pleiotropic and wide spectrum of clinical features. It is autosomal recessively inherited and associated with mutations in ALMS1, a gene involved in cilia functioning. High clinical heterogeneity is the main feature of ALMS. Cone-rod dystrophy with blindness, hearing loss, obesity, insulin resistance and hyperinsulinemia, type 2 diabetes mellitus, hypertriglyceridemia, endocrine abnormalities, cardiomyopathy, and renal, hepatic, and pulmonary anomalies are the most common signs and symptoms.

Meckel Syndrome: A Clinical and Molecular Overview

Meckel syndrome (MKS) is a lethal, autosomal recessive, congenital syndrome caused by mutations in genes that encode proteins structurally or functionally related to the primary cilium. MKS is a malformative syndrome, most commonly characterized by occipital meningoencephalocele, polycystic kidney disease, liver fibrosis, and post- and (occasionally) preaxial polydactyly. To date, more than 10 genes are known to constitute the molecular background of MKS, displaying genetic heterogeneity. Individuals with MKS may resemble some phenotypic features of Joubert syndrome and related disorders, thus making diagnostic setting quite challenging. Here, we systematically reviewed the main clinical and genetic characteristics of MKS and its role among ciliopathies.

Bardet–Biedl Syndrome: A Brief Overview on Clinics and Genetics

Bardet–Biedl syndrome is a genetically pleiotropic disorder characterized by high clinical heterogeneity with severe multiorgan impairment. Clinically, it encompasses primary and secondary manifestations, mainly including retinal dystrophy, mental retardation, obesity, polydactyly, hypogonadism in male, and renal abnormalities. At least 21 different genes have been identified, all involved into primary cilium structure or function. To date, genotype–phenotype correlation is still poor.

How we approach hemangiomas in infants

Pediatric oncologists are increasingly involved in the management of benign vascular tumors and their associated life-threatening complications. Hemangiomas are the most common referring diagnosis to multidisciplinary vascular anomalies clinics. However, as contemporary research has revealed, hemangiomas are not a single, easily defined entity but rather a diverse set of related vascular tumors, each having a unique natural history, growth pattern, and response to therapy. This manuscript seeks to illustrate how we evaluate and manage these complex tumors, their complications, and associated syndromes, while remaining ever vigilant for malignant hemangioma mimickers such as soft tissue sarcomas and congenital leukemia.

The mechanobiological theory: a unifying hypothesis on the pathogenesis of moyamoya disease based on a systematic review

OBJECTIVE

Moyamoya angiopathy (MMA) affects the distal internal carotid artery and is designated as moyamoya disease (MMD) when predisposing conditions are absent, or moyamoya syndrome (MMS) when it occurs secondary to other causes. The authors aimed to investigate the reason for this anatomical site predilection of MMA. There is compelling evidence to suggest that MMA is a phenomenon that occurs due to stereotyped mechanobiological processes. Literature regarding MMD and MMS was systematically reviewed to decipher a common pattern relating to the development of MMA.

METHODS

A systematic review was conducted to understand the pathogenesis of MMA in accordance with PRISMA guidelines. PubMed MEDLINE and Scopus were searched using "moyamoya" and "pathogenesis" as common keywords and specific keywords related to six identified key factors. Additionally, a literature search was performed for MMS using "moyamoya" and "pathogenesis" combined with reported associations. A progressive search of the literature was also performed using the keywords "matrix metalloprotease," "tissue inhibitor of matrix metalloprotease," "endothelial cell," "smooth muscle cell," "cytokines," "endothelin," and "transforming growth factor" to infer the missing links in molecular pathogenesis of MMA. Studies conforming to the inclusion criteria were reviewed.

RESULTS

The literature search yielded 44 published articles on MMD by using keywords classified under the six key factors, namely arterial tortuosity, vascular angles, wall shear stress, molecular factors, blood rheology/viscosity, and blood vessel wall strength, and 477 published articles on MMS associations. Information obtained from 51 articles that matched the inclusion criteria and additional information derived from the progressive search mentioned above were used to connect the key factors to derive a network pattern of pathogenesis.

CONCLUSIONS

Based on the available literature, the authors have proposed a unifying theory for the pathogenesis of MMA. The moyamoya phenomenon appears to be the culmination of an interplay of vascular anatomy, hemodynamics, rheology, blood vessel wall strength, and a plethora of intricately linked mechanobiological molecular mediators that ultimately results in the mechanical process of occlusion of the blood vessel, stimulating angiogenesis and collateral blood supply in an attempt to perfuse the compromised brain.

PHACES Syndrome and Associated Anomalies: Risk Associated With Small and Large Facial Hemangiomas

OBJECTIVE. PHACES syndrome includes posterior fossa malformations, hemangioma, arterial anomalies, coarctation of the aorta and cardiac defects, eye abnormalities, and sternal defect with or without supraumbilical raphe. Usually, brain imaging is performed when facial hemangiomas are larger than 5 cm. Data on associated anomalies regardless of hemangioma size are sparse. The objective of this study was to determine, first, the prevalence of PHACES-like associated anomalies in a large sample of infants with all sizes of segmental facial or periorbital focal infantile hemangioma and, second, whether the cutaneous localization of the hemangioma correlates with the type of anomalies present. MATERIALS AND METHODS. The records of all patients of a vascular anomalies practice who had a diagnosis of segmental facial or periorbital focal infantile hemangioma and who had clinical photographs and brain MRI available were reviewed. The clinical photographs were reviewed to determine the localization by segment and lateralization. MRI was reviewed by two experienced pediatric radiologists. If present, cardiovascular anomalies, sternal defects, and eye anomalies were recorded. The criteria for definite and possible PHACES were used. RESULTS. The study included 122 children (90 girls, 32 boys; mean age, 16.6 months). Forty-five (36.9%) children had a facial infantile hemangioma larger than 5 cm. Twenty-two patients (18.0%) had PHACES or possible PHACES syndrome. Cerebrovascular structural anomalies were seen in 14 of 22 and brain anomalies in 6 of 22 patients with PHACES syndrome but in none and one of the patients in the group without PHACES (p < .001). Cardiovascular anomalies were seen in six patients and ocular anomalies in eight patients. All but one of them had PHACES syndrome. CONCLUSION. Clinical concern about associated extracutaneous anomalies is warranted for all children with facial segmental or periorbital focal infantile hemangiomas, including those with small hemangiomas. Further studies are needed to correlate cerebrovascular anomalies with the clinical evolution of hemangiomas and their effects on cerebral perfusion.

Cutaneous manifestations in Moyamoya angiopathy: A review

BACKGROUND AND PURPOSE

Moyamoya angiopathy (MA) is a progressive cerebrovascular disease with a poorly understood pathophysiology. It is mainly characterized by progressive bilateral stenosis of the terminal intracranial part of the supraclinoid internal carotid arteries and the proximal parts of the middle and anterior cerebral arteries. This results in early-onset ischemic or hemorrhagic strokes. The disease may be idiopathic (known as Moyamoya disease) or associated with other heritable or acquired conditions, including type 1 neurofibromatosis or other RASopathies, sickle cell disease, Down syndrome, or autoimmune disorders (known as Moyamoya syndrome). Apart from the brain, other organ manifestations including cutaneous ones have also been described in MA patients.

MATERIALS AND METHODS

A literature research on PubMed was performed for articles mentioning the cutaneous association in MA and published between 1994 and October 2020.

CONCLUSION

The present review summarizes the cutaneous associations as well as the coincidental dermatological findings seen in MA patients. Those include changes in the epidermis, dermis, or skin appendages for example café-au-lait spots, hypomelanosis of Ito, livedo racemosa, hemangiomas, premature graying of hair, chilblains etc.

Management of PHACES syndrome: Risk of stroke and its prevention from a neurosurgical perspective

BACKGROUND AND OBJECTIVES

A multidisciplinary approach for PHACES is essential. A meticulous diagnostic and treatment protocol for PHACES patients with cerebrovascular anomalies within the intermediate and high risk strata for ischemic stroke is presented. We also differentiate the vasculopathy associated with PHACES syndrome from moyamoya angiopathy.

METHODS

Medical records and radiological imaging were reviewed. After initial magnetic resonance imaging/angiography (MRI/MRA), H₂¹⁵O-PET scan (baseline and Acetazolamide challenge) was performed in three patients and 6-vessel cerebral angiography was performed in two patients. Two patients with significant intracranial cerebrovascular anomalies underwent cerebral revascularization.

RESULTS

Each patient presented with a facial hemangioma at birth and additional cerebrovascular anomalies ranging from hypoplasia to steno-occlusive changes of intracranial cerebral arteries. Additional involvement of the cardiovascular system was observed in two patients. Additional to MRI/MRA, a H₂¹⁵O-PET helped stratify the three patients into intermediate (n=1) and high risk groups (n=2). The high-risk group patients underwent individualized cerebral revascularization for future stroke prevention. The patient in intermediate risk group will be followed. Cerebrovascular angiopathy seen in all patients was typical for PHACES without moyamoya and was not progressive at follow-up.

CONCLUSIONS

Patients within the intermediate and high-risk strata for ischemic stroke must undergo a 6-vessel cerebral angiography and further hemodynamic evaluation to indicate need for cerebral revascularization to prevent ischemic stroke. Non-progressive vasculopathy associated with PHACES can itself be hemodynamically relevant for neurosurgical intervention. This vasculopathy is distinct from moyamoya angiopathy, which can occur in conjunction with PHACES, resulting in concurrent progressive vasculopathy that would otherwise be absent.

Two Cases of Oculofaciocardiodental (OFCD) Syndrome due to X-Linked BCOR Mutations Presenting with Infantile Hemangiomas: Phenotypic Overlap with PHACE Syndrome

Background

Oculofaciocardiodental (OFCD) syndrome is due to mutations in BCOR (BCL-6 corepressor). OFCD has phenotypic overlaps with PHACE syndrome (Posterior fossa anomalies, Hemangioma, Arterial anomalies, Cardiac defects, Eye anomalies). Infantile hemangiomas are a key diagnostic criterion for PHACE, but not for OFCD. A previous study reported two cases of infantile hemangiomas in OFCD, but the authors could not exclude chance association.

Case Presentation

We describe two novel cases of female patients (one initially diagnosed with PHACE syndrome), both of whom had infantile hemangiomas. Ophthalmological findings were consistent with oculofaciocardiodental (OFCD) syndrome. Upon genetic testing, these two females were determined to have X-linked BCOR mutations confirming OFCD syndrome diagnoses.

Conclusion

These case reports add support to the hypothesis that infantile hemangiomas may be a feature of OFCD. BCOR may potentially be within a pathway of genes involved in PHACE syndrome and/or in infantile hemangioma formation.

PHACE syndrome: Infantile hemangiomas associated with multiple congenital anomalies: Clues to the cause

Infantile hemangiomas (IH) are the most common vascular tumor of infancy with an estimated 80,000 annual diagnoses in the United States. The genetic mechanisms underlying IH and the related multi-organ birth defect syndromes, PHACE (an acronym for Posterior fossa brain malformations, segmental facial Hemangiomas, Arterial anomalies, Cardiac defects, Eye anomalies, and sternal clefting or supraumbilical raphe) and LUMBAR (an acronym for Lower body hemangiomas, Urogenital anomalies, Myelopathy, Bone deformities, Anorectal malformations/Arterial anomalies, Renal anomalies) remain unsolved. With advances in next generation sequencing (NGS), genomic alterations have been identified in a wide range of vascular anomaly syndromes. We hypothesize that PHACE is a genetic disorder, caused by somatic mutations, likely in cancer genetic pathways. Identification of the genetic etiology will lead to improved diagnosis in PHACE syndrome and development of targeted therapies for IH and related congenital anomalies.

Natural history of PHACE syndrome: A survey of adults with PHACE

BACKGROUND

Awareness of PHACE syndrome has increased; however, little information exists regarding its natural history, especially in patients over the age of 18. We aim to describe the natural history of PHACE to enhance clinical management and counseling of patients.

METHODS

A cohort of patients ≥ 18 years was identified through the PHACE Syndrome Registry and a Vascular Anomalies Clinic Database. A cross-sectional survey was designed after a review of the literature by PHACE experts (IF, JP, DS). Questions were selected by consensus, and the survey was conducted using the Qualtrics platform and via in-person interviews. A 75% response rate was found.

RESULTS

Eighteen adults-17 females and one transgender male-completed the survey. Respondents ranged in age from 18 to 59, with 24 being the mean age. Eighty-nine percent reported experiencing headaches, and 17% reported experiencing acute but transient symptoms mimicking acute ischemic stroke, later diagnosed as atypical migraines. Thirty-three percent reported hearing loss, and 67% endorsed dental issues. One patient experienced two arterial dissections. Three-fourths who attempted conception were successful, and none of their children had clinical features of PHACE. Because results were based on a retrospective survey, data captured were prone to recall bias and not objective. Results were limited by a small sample size.

CONCLUSIONS

Health care providers should be aware of a possible increased risk of neurovascular complications, including atypical migraines mimicking transient ischemic attacks and arterial dissection, in adults with PHACE. Heritability has not been demonstrated, and future studies are needed to assess the risk of infertility.

Moyamoya angiopathy in PHACE syndrome not associated with RNF213 variants

Moyamoya angiopathy is a rare vasculopathy with stenosis and/or occlusion of bilateral intracranial parts of internal carotid arteries and/or proximal parts of middle and anterior cerebral arteries. PHACE syndrome is characterized by large segmental hemangiomas in the cervical-facial region. Both conditions are known to be associated in rare cases. Recently, it was discussed in the literature that RNF213 variants could be etiologically involved in this association. Here, we describe a childhood case with this rare co-occurrence in which we did not identify any rare RNF213 variant. The clinical and genetic backgrounds are discussed.

Moyamoya syndrome and PHACE syndrome: clinical and radiographic characterization of the intracranial arteriopathy and response to surgical revascularization

OBJECTIVE

PHACE syndrome (PHACES) has been linked to cervical and cerebral vascular anomalies, including persistent embryonic anastomoses and progressive steno-occlusive disease. However, no prior studies have documented the long-term response of PHACES patients with moyamoya disease to surgical revascularization with pial or myosynangiosis. The authors present their experience with 8 consecutive patients with PHACES and moyamoya disease.

METHODS

Retrospective review of patients who underwent pial synangiosis revascularization for moyamoya disease with concurrent diagnosis of PHACES.

RESULTS

A total of 8 patients out of 456 surgically treated moyamoya patients had a diagnosis of PHACES. All patients were female, and their average age at the time of surgical treatment was 9.3 years (range 1.8-25.8 years). Five patients had associated basilar artery anomalies or stenosis. All patients had symptomatic narrowing of the petrous segment of the internal carotid artery with tortuous collateralization. Three patients underwent unilateral pial or myo-synangiosis and 5 underwent bilateral procedures. The average hospital length of stay was 5.0 days (range 3-7 days). There were no postoperative complications. Follow-up ranged from 8 to 160 months (average 56 months). Seven of 8 patients have had follow-up angiograms and all had Matsushima grade A or B collateralization without progression of stenosis in other locations. All patients had reduced cortical FLAIR signal on 6-month follow-up MRI and no evidence of new radiographic or clinical strokes.

CONCLUSIONS

Patients with moyamoya disease and PHACES had an intracranial arteriopathy characterized by ectactic anterior vasculature with concomitant basilar artery stenosis, and were all female. The patients had both radiographic and clinical responses to pial synangiosis. The surgical treatment of these patients can be challenging given facial hemangiomas located near the surgical field. Patients with unilateral disease did not have evidence of progression in other cerebral circulation during the given follow-up period.

Noninvasive Assessment of Hemodynamic Stress Distribution after Indirect Revascularization for Pediatric Moyamoya Vasculopathy

BACKGROUND AND PURPOSE

Indirect revascularization surgery is an effective treatment in children with Moyamoya vasculopathy. In the present study, we hypothesized that DSC-PWI may reliably assess the evolution of CBF-related parameters after revascularization surgery, monitoring the outcome of surgical pediatric patients with Moyamoya vasculopathy. Thus, we aimed to evaluate differences in DSC-PWI parameters, including the hemodynamic stress distribution, in surgical and nonsurgical children with Moyamoya vasculopathy and to correlate them with long-term postoperative outcome.

MATERIALS AND METHODS

Pre- and postoperative DSC parameters of 28 patients (16 females; mean age, 5.5 ± 4.8 years) treated with indirect revascularization were compared with those obtained at 2 time points in 10 nonsurgical patients (6 females; mean age, 6.9 ± 4.7 years). We calculated 4 normalized CBF-related parameters and their percentage variance: mean normalized CBF of the MCA territory, mean normalized CBF of the proximal MCA territory, mean normalized CBF of cortical the MCA territory, and hemodynamic stress distribution. The relationship between perfusion parameters and postoperative outcomes (poor, fair, good, excellent) was explored using 1-way analysis of covariance (P < .05).

RESULTS

A significant decrease of the mean normalized CBF of the proximal MCA territory and hemodynamic stress distribution and an increase of the mean normalized CBF of the cortical MCA territory were observed after revascularization surgery (P < .001). No variations were observed in nonsurgical children. Postoperative hemodynamic stress distribution and its percentage change were significantly different in outcome groups (P < .001).

CONCLUSIONS

DSC-PWI indices show postoperative hemodynamic changes that correlate with clinical outcome after revascularization surgery in children with Moyamoya disease.