Finding the Nidus: Detection and Workup of Non-Central Nervous System Arteriovenous Malformations

OnyxTMGel or Coil versus Hydrogel as Embolic Agents in Endovascular Applications: Review of the Literature and Case Series

This review focuses on the use of conventional gel or coil and "new" generation hydrogel used as an embolic agent in endovascular applications. In general, embolic agents have deep or multidistrict vascular penetration properties as they ensure complete occlusion of vessels by exploiting the patient's coagulation system, which recognises them as substances foreign to the body, thus triggering the coagulation cascade. This is why they are widely used in the treatment of endovascular corrections (EV repair), arteriovenous malformations (AVM), endoleaks (E), visceral aneurysms or pseudo-aneurysms, and embolisation of pre-surgical or post-surgical (iatrogenic) lesions. Conventional gels such as Onyx or coils are now commercially available, both of which are frequently used in endovascular interventional procedures, as they are minimally invasive and have numerous advantages over conventional open repair (OR) surgery. Recently, these agents have been modified and optimised to develop new embolic substances in the form of hydrogels based on alginate, chitosan, fibroin and other polymers to ensure embolisation through phase transition phenomena. The main aim of this work was to expand on the data already known in the literature concerning the application of these devices in the endovascular field, focusing on the advantages, disadvantages and safety profiles of conventional and innovative embolic agents and also through some clinical cases reported. The clinical case series concerns the correction and exclusion of endoleak type I or type II appeared after an endovascular procedure of exclusion of aneurysmal abdominal aortic (EVAR) with a coil (coil penumbra released by a LANTERN microcatheter), the exclusion of renal arterial malformation (MAV) with a coil (penumbra coil released by a LANTERN microcatheter) and the correction of endoleak through the application of Onyx 18 in the arteries where sealing by the endoprosthesis was not guaranteed.

Hemodynamic Study of Cerebral Arteriovenous Malformation: Newtonian and Non-Newtonian Blood Flow

OBJECTIVE

Arteriovenous malformation is a disease of the vascular system that occurs mainly in the cerebral arteries and spine. Numerical simulation as a powerful method is used to investigate the Cerebral Arteriovenous Malformation hemodynamic after occlusion of the abnormality step by step by embolization.

METHODS

The computed tomography (CT) Angiographic imaging data of 2 patients are used and a geometric model is extracted by the Mimics software. Numerical simulation of blood flow is performed in both Newtonian and non-Newtonian models. The Navier-Stokes and continuity governing equations are solved by a finite element method using the COMSOL Multiphysics software (the commercial computational fluid dynamics (CFD) simulation software). To validate the numerical results, the real data on blood flow rate in the feeding artery and draining veins are used, as well as angiographic images at different times.

RESULTS

Regarding the comparison of pressure contours for different occlusions of 0, 30, 50, and 90%, by increasing the amount of occlusion in the nidus, there is an increase in the blood pressure. Regarding the comparison of the blood flow velocity in the feeding artery, draining veins, and inside the AVM nidus for Newtonian and non-Newtonian models, there is a significant difference between these 2 simulations in vessels with smaller dimensions (such as vessels inside the nidus).

CONCLUSIONS

By increasing the amount of nidus occlusion, the blood pressure is increased, so the blood supply process is better. According to a significant difference between the Newtonian and non-Newtonian simulations in vessels with smaller dimensions (such as vessels inside the nidus), therefore, non-Newtonian simulation should be done for different occlusions of 30, 50, and 90%.

Eradication of the nidus in arteriovenous malformations with a dominant outflow vein in the lower extremities using coils and absolute ethanol

OBJECTIVE

In the present study, we summarize our experience in locating the nidus of arteriovenous malformations (AVMs) with a dominant outflow vein (DOV) in the lower extremities and eradicating the nidus with ethanol and coils.

METHODS

Twelve patients with lower extremity AVMs who underwent ethanol embolization combined with DOV occlusion from January 2017 to May 2018 were enrolled in the present study. Selective angiography was used to locate the nidus of the AVMs, which was eradicated using ethanol and coils via the direct puncture pathway. All treated patients underwent postoperative follow-up (mean, 25.5 months; range, 14-37 months).

RESULTS

The 12 patients underwent a total of 29 procedures (mean, 2.4; range, 1-4) with 27 detachable coils and 169 Nester coils (Cook Medical Inc, Bloomington, IN). Of the 12 patients, 7 (58.3%) had a complete response and 5 (41.7%) a partial response. Three patients (25%) had minor complications such as blister and superficial skin ulcers during follow-up. However, they recovered spontaneously and completely. No major complications were recorded.

CONCLUSIONS

Ethanol embolization combined with coil-assisted DOV occlusion has the potential to eradicate the nidus of lower extremity AVMs with acceptable complication rates.

Liquid Embolic Agents for Endovascular Embolization: A Review

Endovascular embolization (EE) has been used for the treatment of blood vessel abnormalities, including aneurysms, AVMs, tumors, etc. The aim of this process is to occlude the affected vessel using biocompatible embolic agents. Two types of embolic agents, solid and liquid, are used for endovascular embolization. Liquid embolic agents are usually injectable and delivered into the vascular malformation sites using a catheter guided by X-ray imaging (i.e., angiography). After injection, the liquid embolic agent transforms into a solid implant in situ based on a variety of mechanisms, including polymerization, precipitation, and cross-linking, through ionic or thermal process. Until now, several polymers have been designed successfully for the development of liquid embolic agents. Both natural and synthetic polymers have been used for this purpose. In this review, we discuss embolization procedures with liquid embolic agents in different clinical applications, as well as in pre-clinical research studies.

Liquid Embolization of Peripheral Arteriovenous Malformations with Ethylene-Vinyl Alcohol Copolymer in Neonates and Infants

In the postnatal period, extensive peripheral arteriovenous malformations (AVM) are associated with high morbidity, especially when localized in the liver. Their urgent treatment is always a challenging problem in neonates and infants. We analyzed four consecutive children aged three days to three years who underwent eight liquid embolization procedures with ethylene-vinyl alcohol copolymer. The AVM were situated on the thoracic wall, in the liver, and on the lower leg. In three cases, the malformations showed total regression. The tibial AVM degenerated widely. If impaired beforehand, cardiac or hepatic function normalized after the interventions. There were no embolization-associated complications such as nontarget embolization or tissue ischemia. We conclude that application of ethylene-vinyl alcohol copolymer seems to be a safe therapeutic option and can be used in neonates and infants with peripheral AVM in consideration of the agent's characteristics. Nevertheless, there are still hardly any data concerning young children.

Tantalum-specific contrast-to-noise ratio or conventional detector dose-driven exposure control in angiography: radiation dose and image quality evaluation in a porcine model

Background

The aim of this animal study was to compare the fluoroscopic image quality (IQ) and radiation dose between a tantalum (Ta)-specific contrast-to-noise ratio-driven exposure control (Ta-CEC) and a detector dose-driven exposure control (DEC) in abdominal angiography.

Methods

Nine angiography scenarios were created in seven anaesthetised pigs using Ta-based embolisation material during percutaneous liver and kidney intervention. Fluoroscopic images were acquired using three DEC protocols with different dose levels and Ta-CEC protocols with different IQ levels, sampled in small steps. Polymethyl-methacrylate and aluminium plates were used to simulate attenuation of three water equivalent thicknesses (WET). Three blinded readers evaluated the IQ of DEC and dose equivalent Ta images and selected the Ta-IQ equivalent image corresponding to the DEC image.

Results

Interobserver agreement for the IQ assessment was 0.43 for DEC, 0.56 for Ta-CEC and for the assessment of incident air kerma at the interventional reference point (K_a,r) for the Ta-IQ equivalent image 0.73. The average IQ of the dose equivalent Ta images was superior compared to the DEC images (p < 0.001) and also for every WET (26, 31, or 36 cm) and dose level (p ≤ 0.022). The average K_a,r for the Ta-IQ equivalent images was 59 ± 16% (mean ± standard deviation) lower compared to the DEC images (p < 0.001).

Conclusions

Compared to DEC, Ta-CEC significantly improved the fluoroscopic depiction of Ta, while maintaining the K_a,r. Alternatively, the K_a,r can be significantly reduced by using Ta-CEC instead of DEC, while maintaining equivalent IQ.

A Computational Framework for Pre-Interventional Planning of Peripheral Arteriovenous Malformations

PURPOSE

Peripheral arteriovenous malformations (pAVMs) are congenital lesions characterised by abnormal high-flow, low-resistance vascular connections-the so-called nidus-between arteries and veins. The mainstay treatment typically involves the embolisation of the nidus, however the complexity of pAVMs often leads to uncertain outcomes. This study aims at developing a simple, yet effective computational framework to aid the clinical decision making around the treatment of pAVMs using routinely acquired clinical data.

METHODS

A computational model was developed to simulate the pre-, intra-, and post-intervention haemodynamics of a patient-specific pAVM. A porous medium of varying permeability was employed to simulate the sclerosant effect on the nidus haemodynamics. Results were compared against clinical data (digital subtraction angiography, DSA, images) and experimental flow-visualization results in a 3D-printed phantom of the same pAVM.

RESULTS

The computational model allowed the simulation of the pAVM haemodynamics and the sclerotherapy-induced changes at different interventional stages. The predicted inlet flow rates closely matched the DSA-derived data, although the post-intervention one was overestimated, probably due to vascular system adaptations not accounted for numerically. The nidus embolization was successfully captured by varying the nidus permeability and increasing its hydraulic resistance from 0.330 to 3970 mmHg s ml-1. The nidus flow rate decreased from 71% of the inlet flow rate pre-intervention to 1%: the flow completely bypassed the nidus post-intervention confirming the success of the procedure.

CONCLUSION

The study demonstrates that the haemodynamic effects of the embolisation procedure can be simulated from routinely acquired clinical data via a porous medium with varying permeability as evidenced by the good qualitative agreement between numerical predictions and both in vivo and in vitro data. It provides a fundamental building block towards a computational treatment-planning framework for AVM embolisation.

Imaging of peripheral vascular malformations - current concepts and future perspectives

Vascular Malformations belong to the spectrum of orphan diseases and can involve all segments of the vascular tree: arteries, capillaries, and veins, and similarly the lymphatic vasculature. The classification according to the International Society for the Study of Vascular Anomalies (ISSVA) is of major importance to guide proper treatment. Imaging plays a crucial role to classify vascular malformations according to their dominant vessel type, anatomical extension, and flow pattern. Several imaging concepts including color-coded Duplex ultrasound/contrast-enhanced ultrasound (CDUS/CEUS), 4D computed tomography angiography (CTA), magnetic resonance imaging (MRI) including dynamic contrast-enhanced MR-angiography (DCE-MRA), and conventional arterial and venous angiography are established in the current clinical routine. Besides the very heterogenous phenotypes of vascular malformations, molecular and genetic profiling has recently offered an advanced understanding of the pathogenesis and progression of these lesions. As distinct molecular subtypes may be suitable for targeted therapies, capturing certain patterns by means of molecular imaging could enhance non-invasive diagnostics of vascular malformations. This review provides an overview of subtype-specific imaging and established imaging modalities, as well as future perspectives of novel functional and molecular imaging approaches. We highlight recent pioneering imaging studies including thermography, positron emission tomography (PET), and multispectral optoacoustic tomography (MSOT), which have successfully targeted specific biomarkers of vascular malformations.

Peripheral Arteriovenous Malformations: Imaging and Endovascular Management Strategies

The peripheral high-flow vascular malformation (HFVM) comprises arteriovenous malformation (AVM) and fistula (AVF), shows varied clinical presentation (ranging from subtle skin lesion to life-threatening congestive heart failure), and frequently poses diagnostic and therapeutic challenges. Importance of assigning a specific diagnosis to the vascular malformation cannot be overstated, as the treatment strategy is based on the type of vascular anomaly. Although the International Society for the Study of Vascular Anomalies (ISSVA) classification system is the most commonly accepted system for classifying congenital vascular anomalies in clinical practice, the Cho–Do et al classification is of utmost help in guiding optimal mode of treatment in peripheral AVM. Although transarterial approach remains the most commonly employed route for peripheral AVM embolization, the role of transvenous and direct percutaneous approach is ever increasing and the final decision on the approach depends on angioarchitecture of the AVM. In this article, we review various commonly employed classification systems for congenital vascular anomalies, and describe clinical features, imaging and treatment strategies for peripheral arteriovenous malformation (PAVM).

Illuminating the nidus: The role of FDG PET/CT in high flow arteriovenous vascular malformations

The appropriate identification and localization of a nidus of a high flow arteriovenous malformation is crucial to guide targeted interventional therapy. However, the nidus of a complex or previously treated HFAVM can be difficult to non-invasively demonstrate on magnetic resonance imaging alone. We describe a unique case of a 56-year-old female with a complex high flow arteriovenous malformation in which we demonstrated the feasibility of fluorodeoxyglucose positron emission tomography/computed tomography to non-invasively delineate the nidus which subsequently guided successful targeted interventional therapy.

Impact of a contrast-to-noise ratio driven and material specific exposure control on image quality and radiation exposure in angiography

Conventional detector-dose driven exposure controls (DEC) do not consider the contrasting material of interest in angiography. Considering the latter when choosing the acquisition parameters should allow for optimization of x-ray quality and consecutively lead to a substantial reduction of radiation exposure. Therefore, the impact of a material-specific, contrast-to-noise ratio (CNR) driven exposure control (CEC) compared to DEC on radiation exposure was investigated. A 3D-printed phantom containing iron, tantalum, and platinum foils and cavities, filled with iodine, barium, and gas (carbon dioxide), was developed to measure the CNR. This phantom was placed within a stack of polymethylmethacrylate and aluminum plates simulating a patient equivalent thickness (PET) of 2.5-40 cm. Fluoroscopy and digital radiography (DR) were conducted applying either CEC or three, regular DEC protocols with parameter settings used in abdominal interventions. CEC protocols where chosen to achieve material-specific CNR values similar to those of DEC. Incident air kerma at the reference point(K_a,r), using either CEC or DEC, was assessed and possible K_a,r reduction for similar CNR was estimated. We show that CEC provided similar CNR as DEC at the same or lower K_a,r. When imaging barium, iron, and iodine K_a,r was substantially reduced below a PET of 20 cm and between 25 cm and 30 cm for fluoroscopy and Dr When imaging platinum and tantalum using fluoroscopy and DR and gas using DR, the K_a,r reduction was substantially higher. We estimate the K_a,r reduction for these materials between 15% and 84% for fluoroscopy and DR between 15% and 93% depending on the PET. The results of this study demonstrate a high potential for skin dose reduction in abdominal radiology when using a material-specific CEC compared to DEC. This effect is substantial in imaging materials with higher energy K-edges, which is beneficial, for example, in long-lasting embolization procedures with tantalum-based embolization material in young patients with arterio-venous malformations.

Fast TWIST with iterative reconstruction improves diagnostic accuracy of AVM of the hand

Very high temporal and spatial resolution is mandatory for the diagnosis of arteriovenous malformations (AVM) of the hand. Until now, magnetic resonance imaging (MRI) has not fulfilled both requirements simultaneously. This study presents how the combination of a very fast TWIST MRI (time-resolved angiography with interleaved stochastic trajectories) sequence and iterative reconstructions optimizes temporal as well as spatial resolution. 11 patients were examined at a 3-T MRI scanner with two different TWIST protocols: the standard and the study protocol, acquiring a data set every 5.57 s and 1.44 s respectively. The study data was retrospectively iteratively reconstructed with different regularization factors (0.001, 0.002, 0.004, 0.008). Results were compared using the sign-test. P-values < 0.05 were regarded statistically significant. With a low amount of contrast medium, the temporal resolution of the study protocol enabled the differentiation of arteries from veins in all patients whereas the signal-to-noise ratio (SNR) deteriorated. Depending on the regularization factors, SNR, delineation of arterial feeders and non-involved hand and interdigital arteries, as well as artefact levels varied. Overall, iterative reconstruction with regularization factor 0.004 achieved the best results, consequently showing the ability of MRI as a reliable diagnostic method in AVMs of the hand.

Update on extracranial arteriovenous malformations: A staged multidisciplinary approach

Arteriovenous malformations (AVMs) are vascular lesions that are thought to arise from congenital errors during development of vessels resulting in abnormal connections between arteries and veins. Though most AVMs develop in the brain or spinal cord, they can occur anywhere in the body. These extracranial or peripheral AVMs have a predilection for the head, neck, and limbs. Since these malformations infiltrate normal soft tissue, management requires selective treatment with preservation of normal surrounding architecture. Therefore, they are best addressed through a staged multimodal and multidisciplinary approach, using a combination of different laser, interstitial, intravascular and surgical techniques to specifically target anomalous vessels. The goal of treatment is overall disease improvement and symptom control with interventions that do not result in outcomes worse than the disease itself. Recently, the discovery of somatic and germline mutations in peripheral AVMs have contributed to a better understanding of the pathophysiology, resulting in promising new pharmacologic treatments. Recent evidence suggests that adjuvant medical therapy can enhance and sustain interventional and/or surgical outcomes. Herein we describe how a new understanding of the etiology and physiology of extracranial AVM provides guidance to current treatment approaches.

Sonography of abdominal wall vascular malformation: a case report and review of the literature

Vascular anomalies are classified as vascular tumors (VT) and vascular malformations (VM). VTs are divided according to their clinical behavior, while VMs are classified according to their flow characteristics, histopathologic features, and associations with other anomalies. Sonography emerges as the diagnostic imaging method of first choice for assessing abdominal wall disorders and masses, thus representing a valuable tool for the diagnosis and follow-up of abdominal wall VMs. In this review, we report a case of abdominal wall arteriovenous malformation (AVM) in a 17-year old and briefly discuss the cases of abdominal wall VMs.

Imaging of Vascular Malformations

Recent advances in imaging have allowed a better understanding of imaging features and classification of vascular anomalies. This article focuses on imaging of vascular malformations; describes the updated classification system and clinical and imaging characteristics of the different subtypes; and discusses the associated syndromes, differential diagnosis, and available treatment options, including the role of imaging in management.

Spectrum of Imaging Manifestations of Vascular Malformations and Tumors Beyond Childhood: What General Radiologists Need to Know

Vascular anomalies encompass a collection of diagnoses that differ greatly in terms of clinical presentation, natural history, imaging findings, and management. The purpose of this article is to review diagnostic imaging findings of vascular malformations and vascular tumors, excluding the central nervous system, that occur beyond childhood. A widely accepted classification system created by the International Society for the Study of Vascular Anomalies provides a framework for this review, focusing on the entities most likely to be encountered by general radiologists, although several rare but clinically important entities are also reviewed.

Congenital Limb Overgrowth Syndromes Associated with Vascular Anomalies

Congenital limb length discrepancy disorders are frequently associated with a variety of vascular anomalies and have unique genetic and phenotypic features. Many of these syndromes have been linked to sporadic somatic mosaicism involving mutations of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway, which has an important role in tissue growth and angiogenesis. Radiologists who are aware of congenital limb length discrepancies can make specific diagnoses based on imaging findings. Although genetic confirmation is necessary for a definitive diagnosis, the radiologist serves as a central figure in the identification and treatment of these disorders. The clinical presentations, diagnostic and imaging workups, and treatment options available for patients with Klippel-Trenaunay syndrome, CLOVES (congenital lipomatous overgrowth, vascular anomalies, epidermal nevi, and scoliosis/spinal deformities) syndrome, fibroadipose vascular anomaly, phosphatase and tensin homolog mutation spectrum, Parkes-Weber syndrome, and Proteus syndrome are reviewed. ^©RSNA, 2019.

Intraosseous Arteriovenous Malformations in the Extremities Managed with Coils and Absolute Ethanol Treatment

BACKGROUND

The extremity intraosseous arteriovenous malformations (AVMs) are rare high flow vascular lesions for which the treatment remains challenging. The aim of the study wasto assess treatment methods, interim results, and complications of coils and absolute ethanol in managing extremity intraosseous AVMs via direct puncture approach.

METHODS

From 2009 to 2017, 12 patients (mean age, 27.5 years; range, 3-54 years) with extremity intraosseous AVMs underwent staged coils and absolute ethanol treatment via the direct puncture approach. All patients were symptomatic before the procedure as per the Schobinger staging system. The mechanical detachable coils and undetachable coils were used first followed by the injection of absolute ethanol used as a sclerosant agent via a direct puncture approach. Follow-up evaluation (6 to 72 months; mean, 23.5 months), including imaging and symptoms and signs, was performed in all patients.

RESULTS

Twenty-seven absolute alcohol procedures were performed for patients with intravascular sclerosis (range: 1-3, mean: 2) with one procedure required per patient (n = 2), 2 per patient (n = 5), or 3 per patient (n = 5). The average stretched length of the total coils per patient was 843.33 cm. The amount of absolute ethanol used ranged from 10 mL to 45 mL (mean, 25.69 mL) in a single session. Nine of twelve patients (75%) exhibited complete responses, and 3 patients (25%) exhibited partial responses. One patient experienced minor complication of transient motor nerve injury and completely recovered half a month later. No major complications occurred.

CONCLUSIONS

The study provides strong evidence, suggesting that direct puncture and coils with absolute ethanol approach is an effective and safe treatment in patients with extremity intraosseous AVMs, yielding minor complications and good results.

Pediatric Hepatobiliary Interventions in the Setting of Intrahepatic Vascular Malformations, Portal Hypertension, and Liver Transplant

Within the broad spectrum of pediatric hepatobiliary disorders, hepatic vascular malformations, portal hypertension, and hepatic transplant interventions pose numerous challenges. The role of interventional radiology within each of these conditions is discussed herein, beginning with endovascular management of high flow hepatic vascular malformations. Next, while becoming less common in adult populations, surgical portoportal and portosystemic shunts remain prevalent in many pediatric centers. Shunt anatomy is reviewed along with endovascular management techniques for shunt dysfunction. Next, the growing experience with pediatric transjugular intrahepatic portosystemic shunt placement is reviewed along with tips for success in pediatric patients. Finally, pediatric hepatic transplant interventions are discussed with technical notes pertinent to split liver anatomy.

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.

Classification and ultrasound findings of vascular anomalies in pediatric age: the essential

Proper nomenclature is a major obstacle in understanding and managing vascular anomalies. Often the same term is used for totally different types of lesions or, conversely, the same lesion may be labeled with different terms. Although in recent times there has been a greater understanding of the problems concerning vascular anomalies, episodes of improper use of terminology still remain. The aim of this article, starting from the most recent classification of vascular anomalies, is to provide a clinical and instrumental approach to identifying these lesions and to converge towards a clear and unambiguous terminology that must become univocal among the various operators to avoid diagnostic misunderstandings and therapeutic errors.

The Use of Transarterial Approaches in Peripheral Arteriovenous Malformations (AVMs)

Arteriovenous malformations (AVMs) are a subset of congenital vascular malformations (CVMs). They comprise abnormal connections between arterial and venous circulation; treatment approaches are dependent on the angioarchitecture of the AVM, specifically the number and arrangement of the feeder arteries and outflow veins. Various imaging modalities can be used to diagnose and plan treatment. Here we will review the use of transarterial approaches to treat AVMs.

Clinical and sonographic features of pediatric soft-tissue vascular anomalies part 2: vascular malformations

Vascular malformations are a heterogeneous group of entities, many of which present in the pediatric age group. Sonography plays a major role in the management of children with these vascular anomalies by providing information that helps in diagnosing them, in assessing lesion extent and complications, and in monitoring response to therapy. The interpretation of sonographic findings requires correlation with clinical findings, some of which can be easily obtained at the time of scanning. This has to be combined with the use of appropriate nomenclature and the most updated classification in order to categorize these patients into the appropriate management pathway. Some vascular malformations are part of combined vascular anomalies or are associated with syndromes that include other disorders, frequently limb overgrowth, and these are now being reclassified based on their underlying genetic mutation. Sonography has limitations in the evaluation of some vascular malformations and in these cases MR imaging might be considered the imaging modality of choice, particularly for lesions that are large, that involve multiple compartments or are associated with other soft-tissue and bone abnormalities. In this article, which is part 2 of a two-part series, the authors review the most relevant clinical and sonographic features of arteriovenous, capillary, venous and lymphatic malformations as well as vascular malformations that are part of more complex conditions or associated with syndromes, including Parkes-Weber syndrome, phosphatase and tensin homologue (PTEN) hamartoma tumor syndromes, Klippel-Trénaunay syndrome, CLOVES (congenital lipomatous overgrowth, vascular malformations, epidermal nevi and skeletal anomalies) syndrome, fibro-adipose vascular anomaly and Proteus syndrome.