Clinical spectrum of capillary malformation-arteriovenous malformation syndrome presenting to a pediatric dermatology practice: a retrospective study

A case of large airway and orbital hemangiomas with facial capillary malformation

Infantile hemangiomas (IHs) are the most common pediatric vascular tumors, although their genetic etiology is largely unknown. Congenital capillary malformations (CMs) are associated with known somatic pathogenic variants, including GNAQ, GNA11, PIK3CA, and PIK3R1. Co-occurrence of a facial CM such as port wine stain and IH is not associated with any recognized vascular anomaly syndromes and rarely reported in the literature. We describe a case of a 5-week-old female patient with a large facial CM and extensive IHs of the lower lip, airway, and orbit who presented with airway compromise and responded to propranolol therapy.

Prenatal Clinical Findings in RASA1-Related Capillary Malformation-Arteriovenous Malformation Syndrome

Pathogenic variants in RASA1 are typically associated with a clinical condition called “capillary malformation-arteriovenous malformation” (CM-AVM) syndrome, an autosomal dominant genetic disease characterized by a broad phenotypic variability, even within families. In CM-AVM syndrome, multifocal capillary and arteriovenous malformations are mainly localized in the central nervous system, spine and skin. Although CM-AVM syndrome has been widely described in the literature, only 21 cases with prenatal onset of clinical features have been reported thus far. Here, we report four pediatric cases of molecularly confirmed CM-AVM syndrome which manifested during the prenatal period. Polyhydramnios, non-immune hydrops fetalis and chylothorax are only a few possible aspects of this condition, but a correct interpretation of these prenatal signs is essential due to the possible fatal consequences of unrecognized encephalic and thoracoabdominal deep vascular malformations in newborns and in family members carrying the same RASA1 variant.

Arteriovenous Malformations-Current Understanding of the Pathogenesis with Implications for Treatment

Arteriovenous malformations are a vascular anomaly typically present at birth, characterized by an abnormal connection between an artery and a vein (bypassing the capillaries). These high flow lesions can vary in size and location. Therapeutic approaches are limited, and AVMs can cause significant morbidity and mortality. Here, we describe our current understanding of the pathogenesis of arteriovenous malformations based on preclinical and clinical findings. We discuss past and present accomplishments and challenges in the field and identify research gaps that need to be filled for the successful development of therapeutic strategies in the future.

Capillary malformation-arteriovenous malformation syndrome: a multicentre study

BACKGROUND

Capillary malformation-arteriovenous malformation (CM-AVM) syndrome is a rare syndrome with characteristic skin lesions that are associated with fast-flow vascular malformations (FFVMs) in one-third of patients. Few case series have been described, and none in Spain.

AIM

To identify the prevalence of dermatological parameters, FFVMs and associated features in a large series of patients with CM-AVM.

METHODS

We conducted an observational study of patients with CM-AVM syndrome diagnosed in 15 Spanish hospitals over 3 years. The main clinical, radiological, genetic findings and associated diseases were analysed.

RESULTS

In total, 64 patients were assessed. In 26.5% of cases, the diagnosis was incidental. In 75% of patients, there was one significantly larger macule, which we termed the 'herald patch'. FFVMs were detected in 34% of the patients, with 30% located on the skin, 7.8% in the brain and in 1.5% in the spine. There was a positive family history in 65% of the 64 patients. Genetic analysis was performed for RASA1 mutations in 57 patients, of whom 42 (73%) had a positive result. All 4 patients tested for EPHB4 mutations had a positive result. No tumour lesions were detected in the series, except for five infantile haemangiomas.

CONCLUSIONS

Our data on clinical lesions, associated FFVM, family history and genetics are similar to those previously published in the literature. An extensive data analysis failed to demonstrate any statistically significant association between the presence of an FFVM and any clinical, familial or genetic parameter that could predict its onset, although a link between the presence of a herald patch on the midline face and the presence of a brain FFVM was observed. We did not detect any genotype-phenotype correlation.

Characterization of vascular stains associated with high flow

BACKGROUND

High-flow vascular stains (HFVS) are lesions that have the appearance of capillary malformations/port wine stains but are associated with increased arterial flow.

OBJECTIVE

To identify features of HFVS that differentiate them from typical "slow-flow" port wine stains.

METHODS

Retrospective multicenter cohort study of HFVS evaluated across 7 centers was conducted. HFVS were characterized by clinical features (warmth, thrill, rapid capillary refill), radiologic findings (fast flow), or mutations associated with capillary malformation-arteriovenous malformation syndrome. Investigators reviewed photographs.

RESULTS

The study reviewed 70 patients with HFVS (47 multifocal and 23 solitary). Most were flat (77%), warm to the touch (60%), and red or pink-red in color (35%), with heterogeneous color saturation (73%) and well-defined borders (71%). Regional soft tissue swelling/overgrowth was common (47%). Head and neck location was most common (38%). Among 34 HFVS with photographic review over time, all demonstrated changes in appearance.

LIMITATIONS

Retrospective design, recall bias, lack of standardized time points or visual analog scale, and image variability.

CONCLUSION

Heterogeneity of stain color saturation, warmth to touch, peripheral pallor, and overgrowth/soft tissue swelling help distinguish HFVS from port wine stains. Darkening of color and increased border demarcation may develop over time. These findings raise suspicion for HFVS and provide an indication to assess for extracutaneous involvement.

Good response to pulsed dye laser in patients with capillary malformation-arteriovenous malformation syndrome (CM-AVM)

Capillary malformation-arteriovenous malformation syndrome (CM-AVM) is an autosomal dominant disorder caused by heterozygous mutations in RASA1 and EPHB4. Capillary stains in CM-AVM are compatible with Schöbinger's phase I AVMs. Vascular laser has been classically contraindicated for the treatment of AVMs, as there is a fear of accelerating their progression. In this study, we have treated capillary stains in five CM-AVM patients with pulsed dye laser, with improvement and without worsening or recurrence of the lesions after 1 year of clinical and ultrasound follow-up.

Brief Description of ISSVA Classification for Radiologists

Ongoing discovery regarding the origin and treatment of vascular anomalies requires standardized nomenclature which itself must undergo iterative updating. This article introduces the 2018 International Society for the Study of Vascular Anomalies (ISSVA) classification, emphasizing the biologic basis of vascular anomalies, summarizing the key features of commonly encountered entities, and serving as a foundation for subsequent articles presented herein. Vascular tumors are discussed to highlight their distinction from vascular malformations which will receive greater attention with respect to management and technical considerations within the issue.

A Pathogenic Homozygous Mutation in The Pleckstrin Homology Domain of RASA1 Is Responsible for Familial Tricuspid Atresia in An Iranian Consanguineous Family

Objective

Tricuspid atresia (TA) is a rare life-threatening form of congenital heart defect (CHD). The genetic mechanisms underlying TA are not clearly understood. According to previous studies, the endocardial cushioning event, as the primary sign of cardiac valvulogenesis, is governed by several overlapping signaling pathways including Ras/ ERK pathway. RASA1, a regulator of cardiovascular development, is involved in this pathway and its haploinsufficiency (due to heterozygous mutations) has been identified as the underlying etiology of the autosomal dominant capillary malformation/arteriovenous malformation (CM/AVM).

Materials and Methods

In this prospective study, we used whole exome sequencing (WES) followed by serial bioinformatics filtering steps for two siblings with TA and early onset CM. Their parents were consanguineous which had a history of recurrent abortions. Patients were carefully assessed to exclude extra-cardiac anomalies.

Results

We identified a homozygous RASA1 germline mutation, c.1583A>G (p.Tyr528Cys) in the family. This mutation lies in the pleckstrin homology (PH) domain of the gene. The parents who were heterozygous for this variant displayed CM.

Conclusion

This is the first study reporting an adverse phenotypic outcome of a RASA1 homozygous mutation. Here, we propose that the phenotypic consequence of the homozygous RASA1 p.Tyr528Cys mutation is more serious than the heterozygous type. This could be responsible for the TA pathogenesis in our patients. We strongly suggest that parents with CM/AVM should be investigated for RASA1 heterozygous mutations. Prenatal diagnosis and fetal echocardiography should also be carried out in the event of pregnancy in heterozygous parents.

Update on classification and diagnosis of vascular malformations

PURPOSE OF REVIEW

This review provides an update of the classification in the classification of vascular anomalies since April 2014 at the International Society for the Study of Vascular Anomalies meeting in Melbourne, Australia.

RECENT FINDINGS

The reader will become familiar with how to diagnose the major vascular malformations, including capillary, venous, arteriovenous, and lymphatic and combinations thereof. In addition, vascular malformation syndromes, including those with overgrowth, will be clarified.

SUMMARY

Vascular malformations are common. Capillary malformations are now better understood through an updated classification. Verrucous hemangioma is truly a venulocapillary malformation that extends into the subcutis. PIK3Ca-Related Overgrowth Syndromes encompass Klippel-Trenaunay, Congenital Lipomatous Asymmetric Overgrowth of the Trunk with Lymphatic, Capillary, Venous, and Combined-Type Vascular Malformations, Epidermal Nevi, Scoliosis/Skeletal and Spinal Anomalies, Megalencephaly-Capillary Malformation-Polymicrogyria Syndrome (M-CAP), fibroadipose hyperplasia, and macrodactyly. Yet another syndrome should be highlighted: Capillary Malformation of the Lower Lip, Lymphatic Malformation of the Face and Neck, Asymmetry and Partial/Generalized Overgrowth. Knowledge of the genetic basis of vascular malformations will lead to future treatments.

The categories of cutaneous mosaicism: A proposed classification

Mosaic disorders can most easily be studied in the skin. This article presents a comprehensive overview of the different forms of cutaneous mosaicism. Major categories are genomic versus epigenetic mosaicism and nonsegmental versus segmental mosaicism. The class of nonsegmental mosaics includes single point mosaicism as exemplified by solitary benign or malignant skin tumors; disseminated mosaicism as noted in autosomal dominant tumor syndromes such as neurofibromatosis 1; and patchy mosaicism without midline separation as found in giant melanocytic nevus. The class of segmental mosaics includes segmental manifestation of lethal genes surviving by mosaicism as noted in Proteus syndrome; type 1 segmental mosaicism of autosomal dominant skin disorders reflecting heterozygosity for a postzygotic new mutation; type 2 segmental mosaicism of autosomal dominant skin disorders reflecting loss of heterozygosity that occurred at an early developmental stage in a heterozygous embryo; and isolated or superimposed segmental mosaicism of common polygenic skin disorders such as psoriasis or atopic dermatitis. A particular form of genomic mosaicism is didymosis (twin spotting). Revertant mosaicism is recognizable as one or more areas of healthy skin in patients with epidermolysis bullosa or other serious genodermatoses. The category of epigenetic mosaicism includes several X-linked, male lethal disorders such as incontinentia pigmenti, and the patterns of lyonization as noted in X-linked non-lethal disorders such as hypohidrotic ectodermal dysplasia of the Christ-Siemens-Touraine type. An interesting field of future research will be the concept of epigenetic autosomal mosaicism that may explain some unusual cases of autosomal transmission of linear hypo- or hypermelanosis.

Multifocal capillary malformations in an older, asymptomatic child with a novel RASA1 mutation

Multifocal capillary malformation (CM) is the cardinal feature of patients with RASA1 mutations. These CMs are ‘red flags’, signalling the possible association with an arteriovenous malformation (AVM) or an arteriovenous fistula (AVF). We report an 8‐year‐old boy who presented with > 20 CMs, who was found to have a novel mutation in the RASA1 gene. Radiological screening of children with RASA1 mutations is not standardized, and we elected to carry out baseline magnetic resonance imaging of the brain and spine in our case, which gave normal results. We discuss the recent literature and our approach in the management of such a case.