[Management of vascular anomalies in children]

Vascular anomalies, which are broadly identified as "angiomas", are rare entities and often unknown by the medical sphere. They are divided in two different categories which carry different prognosis and management: "vascular tumors" and "vascular malformations". Their precise identification is crucial and involves a good knowledge of the biological classification published by Mulliken and Glowacki and that has recently been updated by the International Society for the Study of Vascular Anomalies (ISSVA). Vascular tumors are benign, common, inborn or not and most of the time disappear with growth. Vascular malformations are always congenital and growth with the child. They can involve type of vessels solely or combined with others. A rheologic differentiation between slow and fast flow malformations is essential in order to characterize the seriousness of the lesion. Frequently, their diagnosis is clinically established and the anamnesis is conducted to answer three questions that are the time of revelation of the lesion ("When?"), its aspect ("What?") and its evolution ("How?"). Further investigations are usually not required but a non-invasive imaging technique such as Doppler ultrasound could be useful if a doubt exists. Surgery is not mandatory and must always be well thought because its consequences might be disastrous. It must be left to cosmetic sequelae of these lesions or to lesions that are totally resectable without causing any unacceptable deformation.

Common somatic alterations identified in maffucci syndrome by molecular karyotyping

Maffucci syndrome (MS) is a rare congenital disorder characterized by multiple central cartilaginous tumors (enchondromas) in association with cutaneous spindle cell hemangiomas. These patients have a high incidence of malignant transformation. No familial case is known and the etiopathogenic cause remains unknown. In enchondromatosis (Ollier disease, OD), which is comprised of enchondromas only, 4 mutations in the PTHR1 gene have been identified in 4 patients; 3 were somatic and 1 was germline. No PTHR1 mutations have been detected in MS, whereas somatic IDH1 and, more rarely, IDH2 mutations have been observed in 77% of patients with MS and 81% of patients with OD. These genetic alterations are shared with other tumors, including glioma, leukemia and carcinoma. To search for underlying somatic genomic causes, we screened MS tissues using Affymetrix SNP-chips. We looked for CNVs, LOH and uniparental isodisomy (UPID) by performing pairwise analyses between allelic intensities in tumoral DNA versus the corresponding blood-extracted DNA. While common chromosomal anomalies were absent in constitutional DNA, several shared CNVs were identified in MS-associated tumors. The most frequently encountered somatic alterations were localized in 2p22.3, 2q24.3 and 14q11.2, implicating these chromosomal rearrangements in the formation of enchondromas and spindle cell hemangiomas in MS. In one chondrosarcoma specimen, large amplifications and/or deletions were observed in chromosomes 3, 6, 9, 10, 12, 13, and 19. Some of these genetic changes have been reported in other chondrosarcomas suggesting an etiopathogenic role. No LOH/UPID was observed in any Maffucci tissue. Our findings identify frequent somatic chromosomal rearrangements on 2p22.3, 2q24.3 and 14q11.2, which may unmask mutations leading to the lesions pathognomonic of MS.

Mutations in the VEGFR3 signaling pathway explain 36% of familial lymphedema

Lymphedema is caused by dysfunction of lymphatic vessels, leading to disabling swelling that occurs mostly on the extremities. Lymphedema can be either primary (congenital) or secondary (acquired). Familial primary lymphedema commonly segregates in an autosomal dominant or recessive manner. It can also occur in combination with other clinical features. Nine mutated genes have been identified in different isolated or syndromic forms of lymphedema. However, the prevalence of primary lymphedema that can be explained by these genetic alterations is unknown. In this study, we investigated 7 of these putative genes. We screened 78 index patients from families with inherited lymphedema for mutations in FLT4, GJC2, FOXC2, SOX18, GATA2, CCBE1, and PTPN14. Altogether, we discovered 28 mutations explaining 36% of the cases. Additionally, 149 patients with sporadic primary lymphedema were screened for FLT4, FOXC2, SOX18, CCBE1, and PTPN14. Twelve mutations were found that explain 8% of the cases. Still unidentified is the genetic cause of primary lymphedema in 64% of patients with a family history and 92% of sporadic cases. Identification of those genes is important for understanding of etiopathogenesis, stratification of treatments and generation of disease models. Interestingly, most of the proteins that are encoded by the genes mutated in primary lymphedema seem to act in a single functional pathway involving VEGFR3 signaling. This underscores the important role this pathway plays in lymphatic development and function and suggests that the unknown genes also have a role.

Germline Mutations in RASA1 Are Not Found in Patients with Klippel-Trenaunay Syndrome or Capillary Malformation with Limb Overgrowth

The RASA1 gene encodes p120RASGAP, a multidomain cytoplasmic protein that acts as a negative regulator of the RAS signalling pathway. Heterozygous loss-of-function RASA1 mutations were identified in patients with Parkes Weber syndrome and multifocal capillary malformations. This syndrome is characterised by a capillary blush on an extremity, arteriovenous microfistulas, and bony and soft tissue hypertrophy. The aim of this study was to test RASA1 in 2 disorders characterised by asymmetric limb enlargement and vascular malformations, namely Klippel-Trenaunay syndrome and regional capillary malformation with overgrowth. We did not identify any clear pathogenic change in these patients. Thus, besides clinical and radiological criteria, RASA1 testing constitutes an additional tool to differentiate Parkes Weber syndrome of capillary malformation-arteriovenous malformation (CM-AVM) from overlapping disorders.

Variable Somatic TIE2 Mutations in Half of Sporadic Venous Malformations

Venous malformations (VMs) are the most frequent vascular malformations referred to specialized vascular anomaly centers. A rare (1-2%) familial form, termed cutaneomucosal venous malformation (VMCM), is caused by gain-of-function mutations in TIE2. More recently, sporadic VMs, characterized by the presence of large unifocal lesions, were shown to be caused by somatic mutations in TIE2. These include a frequent L914F change, and a series of double mutations in cis. All of which cause ligand-independent receptor hyperphosphorylation in vitro. Here, we expanded our study to assess the range of mutations that cause sporadic VM. To test for somatic changes, we screened the entire coding region of TIE2 in cDNA from resected VMs by direct sequencing. We detected TIE2 mutations in 17/30 (56.7%) of the samples. In addition to previously detected mutations, we identified 7 novel somatic intracellular TIE2 mutations in sporadic VMs, including 3 that cause premature protein truncation.

Genotypes and phenotypes of 162 families with a glomulin mutation

A decade ago, we identified a novel gene, glomulin (GLMN) in which mutations cause glomuvenous malformations (GVMs). GVMs are bluish-purple cutaneous vascular lesions with characteristic glomus cells in the walls of distended venous channels. The discovery of the genetic basis for GVMs allowed the definition of clinical features to distinguish GVMs from other venous anomalies. The variation in phenotype was also highlighted: from a single punctate blue dot to a large plaque-like lesion. In this study, we screened GLMN in a large cohort of patients to broaden the spectrum of mutations, define their frequency and search for possible genotype-phenotype correlations. Taking into account 6 families published by others, a mutation in GLMN has been found in 162 families. This represents 40 different mutations; the most frequent one being present in almost 45% of them. Expressivity varies largely, without a genotype/phenotype relationship. Among 381 individuals with a mutation, we discovered 37 unaffected carriers, implying a penetrance of 90%. As nonpenetrant individuals may transmit the disease to their descendants, knowledge on the mutational status is needed for appropriate genetic counseling.

A novel association between RASA1 mutations and spinal arteriovenous anomalies

BACKGROUND AND PURPOSE

CM-AVM is a recently recognized autosomal dominant disorder associated with mutations in RASA1. Arteriovenous lesions have been reported in the brain, limbs, and the face in 18.5% of patients. We report a novel association between RASA1 mutations and spinal arteriovenous anomalies.

MATERIALS AND METHODS

In a collaborative study, 5 index patients (2 females, 3 males) with spinal AVMs or AVFs and cutaneous multifocal capillary lesions were investigated for the RASA1 gene mutation.

RESULTS

All 5 patients were found to have RASA1 mutation (2 de novo, 3 familial), and all had multifocal capillary malformations at birth. Neurologic deficits developed at ages ranging from infancy to early adulthood. All spinal anomalies (2 AVMs at the conus, 1 AVM at the lumbosacral junction, and 1 cervical and 1 cervicothoracic AVF) were complex, extensive, and fast-flow lesions. All patients required treatment based on the clinical and/or radiologic appearance of the lesions.

CONCLUSIONS

To our knowledge, an association of RASA1 mutation and spinal AVM/AVF has not been described. MR imaging screening of patients with characteristic CMs and neurologic symptoms presenting at a young age may be useful in detecting the presence of fast-flow intracranial or intraspinal arteriovenous anomalies before potentially significant neurologic insult has occurred.

Recessive primary congenital lymphoedema caused by a VEGFR3 mutation

BACKGROUND

Heterozygous mutations in VEGFR3 have been identified in some familial cases with dominantly inherited primary congenital lymphoedema, known as Nonne-Milroy disease. Recessive cases of primary lymphoedema with a genetic cause are not known, except for two families with syndromic hypotrichosis-lymphoedema-telangiectasia, with a SOX18 mutation.

METHODS AND RESULTS

In this study, we present the first case of isolated primary congenital lymphoedema with recessive inheritance, caused by a homozygous mutation in VEGFR3. The novel mutation is a transition from alanine-to-threonine in amino acid 855, located in the ATP binding domain of the VEGFR3 receptor. Assessment of receptor function showed impaired ligand induced internalisation and ERK1/2 activity. Moreover, receptor phosphorylation was reduced, although less so than for a kinase-dead VEGFR3 mutation, which causes Nonne-Milroy disease.

CONCLUSION

A hypomorphic VEGFR3 mutation, with moderate effect on receptor function, in a homozygous state can result in insufficient lymphatic functioning. Thus, in addition to Nonne-Milroy disease with dominant inheritance, VEGFR3 alterations can cause isolated recessive primary congenital lymphoedema. These data expand our understanding of the aetiology of congenital lymphoedema and suggest that large scale screening of VEGFR3 in all primary lymphoedema patients is necessary.

Hereditary lymphedema type I associated with VEGFR3 mutation: the first de novo case and atypical presentations

Mutations in the vascular endothelial growth factor receptor 3 gene, VEGFR3/FLT4, have been identified in a subset of families with hereditary lymphedema type I or Milroy disease (MIM 153100). Individuals carrying a VEGFR3 mutation exhibit congenital edema of the lower limbs, usually bilaterally and below the knees, sometimes associated with cellulitis, prominent veins, papillomatosis, upturned toenails, and hydrocele. In this study, we report the first de novo VEGFR3 mutation in a patient with sporadic congenital lymphedema. We also describe three other families with a VEGFR3 mutation. In each family, one individual had an atypical clinical presentation of hereditary lymphedema type I, whereas the others had the classical VEGFR3 mutation-caused phenotype. The atypical presentations included pre-natal pleural effusion, spontaneous resorption of lymphedema and elephantiasis. Three of the four identified mutations were novel. These data show that de novo VEGFR3 mutations may be present in patients without family history of congenital lymphedema. This has implications for follow-up care, as such individuals have nearly a 50% risk for occurrence of lymphedema in their children. Our findings also indicate that although most patients with a VEGFR3 mutation have the well-defined phenotype for hereditary lymphedema type I, there are exceptions that should be considered in genetic counseling. Because VEGFR3 mutation can cause generalized lymphatic dysfunction and can thus result in hydrops fetalis, VEGFR3 screening should be added to the investigation of cases of hydrops fetalis of an unknown etiology.

Four common glomulin mutations cause two thirds of glomuvenous malformations ("familial glomangiomas"): evidence for a founder effect

BACKGROUND

Glomuvenous malformation (GVM) ("familial glomangioma") is a localised cutaneous vascular lesion histologically characterised by abnormal smooth muscle-like "glomus cells" in the walls of distended endothelium lined channels. Inheritable GVM has been linked to chromosome 1p21-22 and is caused by truncating mutations in glomulin. A double hit mutation was identified in one lesion. This finding suggests that GVM results from complete localised loss of function and explains the paradominant mode of inheritance.

OBJECTIVE

To report on the identification of a mutation in glomulin in 23 additional families with GVM.

RESULTS

Three mutations are new; the others have been described previously. Among the 17 different inherited mutations in glomulin known up to now in 43 families, the 157delAAGAA mutation is the most common and was present in 21 families (48.8%). Mutation 108C-->A was found in five families (11.8%), and the mutations 554delA+556delCCT and 1179delCAA were present together in two families (4.7% each). Polymorphic markers suggested a founder effect for all four mutations.

CONCLUSIONS

Screening for these mutations should lead to a genetic diagnosis in about 70% of patients with inherited GVM. So far, a mutation in glomulin has been found in all GVM families tested, thus demonstrating locus homogeneity.

Koilocytosis and squamous (pre)neoplasia as detected in population-based cervical screening: practice and theory

INTRODUCTION

Koilocytosis (cavitation of the cytoplasm due to active HPV infection) can be detected in the screening process for cervical carcinoma.

OBJECTIVE

To report the practice of detection of koilocytosis and (pre)neoplasia in population screening and to exploit the collected data to propose an explanation for the relationship between HPV infection and nuclear precancerous changes.

STUDY DESIGN

Centrally collected and stored (SBBW, Leiden, the Netherlands) data from all smears of six regional pathology laboratories (1995-2002), coded according to KOPAC (the national cervical smear coding system; S1: normal thru S9: invasive carcinoma) were accessed. Prevalences per 100,000 smears were calculated for koilocytosis and for squamous abnormalities after stratification for country of origin of screenees. The relative risk (RR) for the ethnic (age) groups was computed by dividing the prevalence of the relevant ethnic (age) group by the prevalence of all women.

RESULTS

Surinamese women featured the highest prevalence of koilocytosis and of all squamous abnormalities. Moroccan women the lowest. The RR for koilocytosis was highest at 30 years (1.84) and lowest at 60 (0.26). RR dependence on age of S5-S9 lesions was similar. Compared to nonkoilocytotic smears, koilocytosis was 104 times more frequent in the 1,500 S4 smears, 36x more frequent in the 6,700 S2-S3 smears, and 24x more frequent in the 1,740 S5-S9 smears. In all three categories this difference is statistically significant.

CONCLUSION

High prevalences for both koilocytosis and for preneoplasia were detected in Surinamese immigrants, however, it still does not exclude HPV infection as a confounder linked to sexual lifestyle. The presence of koilocytosis in cervical smears may serve to identify patients with an increased risk for cervical cancer and perhaps warrant more intensive surveillance than what is provided through five-yearly screening.

LDL receptor-related protein 5 (LRP5) affects bone accrual and eye development

In humans, low peak bone mass is a significant risk factor for osteoporosis. We report that LRP5, encoding the low-density lipoprotein receptor-related protein 5, affects bone mass accrual during growth. Mutations in LRP5 cause the autosomal recessive disorder osteoporosis-pseudoglioma syndrome (OPPG). We find that OPPG carriers have reduced bone mass when compared to age- and gender-matched controls. We demonstrate LRP5 expression by osteoblasts in situ and show that LRP5 can transduce Wnt signaling in vitro via the canonical pathway. We further show that a mutant-secreted form of LRP5 can reduce bone thickness in mouse calvarial explant cultures. These data indicate that Wnt-mediated signaling via LRP5 affects bone accrual during growth and is important for the establishment of peak bone mass.

Molecular genetics of vascular malformations

Vascular malformations are localized errors of angiogenic development. Most are cutaneous and are called vascular 'birthmarks'. These anomalies are usually obvious in the newborn, grow commensurately with the child, and gradually expand in adulthood (Mulliken and Glowacki, 1982). Vascular malformations also occur in visceral organs, such as the respiratory and gastrointestinal tract, but are more common in the brain (Mulliken and Young, 1988). These anomalies are composed of tortuous vascular channels of varying size and shape, lined by a continuous endothelium and surrounded by abnormal complement of mural cells. Vascular malformation can be life threatening due to obstruction, bleeding or congestive heart failure. Most anomalies occur sporadically, but there are families exhibiting autosomal dominant inheritance. Genetic studies of such families have resulted in the identification of mutated genes, directly giving proof of their important role in the regulation of angiogenesis.

Noninvoluting congenital hemangioma: a rare cutaneous vascular anomaly

The authors studied a rare, congenital, cutaneous vascular anomaly that grows proportionately with the child and does not regress. A total of 53 patients were compiled from three vascular anomaly centers. These patients' lesions were analyzed for presentation, physical findings, radiologic and histopathologic characteristics, natural history, and outcome after resection. The lesions occurred slightly more often in male patients, always appeared alone, and were located (in order of frequency) in the head/neck region, extremities, and trunk. They were round-to-ovoid in shape, were plaque-like or bossed, occurred in variable shades of pink to purple, and had an average diameter of 5 cm. The overlying skin was frequently punctuated by coarse telangiectasia, often with central or peripheral pallor. The lesions were warm on palpation; fast-flow was further documented by Doppler ultrasonography. Magnetic resonance imaging and angiographic findings were similar to those of common hemangioma of infancy. All lesions were easily excised without recurrence.Histologic examination revealed lobular collections of small, thin-walled vessels with a large, often stellate, central vessel. Interlobular areas contained predominantly dilated, often dysplastic veins; arteries were also increased in number. Small arteries were observed "shunting" directly into lobular vessels or into abnormal extralobular veins. "Hobnailed" endothelial cells lined the small intralobular vessels. Mast cells were increased. Tests for glucose transporter-1, a recently reported reliable marker for common hemangioma of infancy, were negative in all 26 specimens examined. In conclusion, the authors think these clinicopathologic and radiologic features define a rare vascular lesion for which the term "noninvoluting congenital hemangioma" is proposed. These lesions of intrauterine onset may be a variant of common hemangioma of infancy or another hemangiomatous entity with persistent fast-flow.

Ethanol sclerotherapy of venous malformations: evaluation of systemic ethanol contamination

PURPOSE

To evaluate blood ethanol concentrations immediately after percutaneous ethanol sclerotherapy of venous malformations (VMs).

MATERIALS AND METHODS

Thirty consecutive sclerotherapy procedures were performed for VMs in various anatomic sites. In a prospective study, the blood parameters monitored were ethanol plasma level (immediately after the procedure), plasma haptoglobin (Hp; before and after the procedure), and standard blood analysis including urea, creatinine, bilirubin, and lactic dehydrogenase (LDH) levels during the hospital stay.

RESULTS

The mean amount of 94% ethanol injected was 19.7 mL (0.03-0.78 g/kg of body weight). The observed systemic ethanol levels ranged from 0 to 1.16 g/L (mean, 0.33 g/L, SD = 0.33). The relationship between the observed plasmatic ethanol level (ETOH plasma) measured immediately after the procedure and the maximum expected plasmatic ethanol amount (ETOH max) was linear and significant (correlation coefficient r = 0.91 for all lesions, r = 0.96 for lesions without visible venous drainage, r = 0.86 for lesions with visible draining veins, and r = 0.93 for lobulated VMs). Minimal changes were observed for indicators of hemolysis: macroscopic hemoglobinuria in five of 30, abnormal Hp level in seven of 30, and increase in LDH and increase in bilirubinemia in one case each.

CONCLUSIONS

Systemic ethanol contamination during sclerotherapy of VMs could be detected in 25 of 30 cases (83.3%). The plasmatic ethanol level was directly proportional to the amount of ethanol injected and not dependent on the VM morphology, venous drainage, or injection technique. Clinicians and interventional radiologists must be aware of this massive ethanol outflow during percutaneous sclerotherapy of VMs and its potentially serious systemic complications.

Linkage disequilibrium narrows locus for venous malformation with glomus cells (VMGLOM) to a single 1.48 Mbp YAC

Venous malformations with glomus cells are localised cutaneous lesions of vascular dysmorphogenesis. They are usually sporadic, but sometimes familial. Using five families, we mapped the locus, VMGLOM, to chromosome 1p21-p22. In order to refine this locus, spanning 4-6 Mbp, we then studied seven additional families. They exhibited linkage to VMGLOM and the combined lod score for all 12 families was 18.41 at theta = 0.0 for marker D1S188. We found a distinct haplotype shared by seven families, comprising seven alleles which are rare in the general population (P < 0.01). This indicates that the haplotype is identical by descent in all seven families, and hence the locus can be refined by inferring ancestral crossovers. Using this approach, we position the causative gene between two markers on the same non-chimeric YAC of 1.48 Mbp, a feasible size for positional cloning. As there is no known gene involved in vasculogenesis and/or angiogenesis in this YAC, the identification of the causative gene is likely to reveal a novel regulator or vascular development.

KRIT1 is mutated in hyperkeratotic cutaneous capillary-venous malformation associated with cerebral capillary malformation

Hyperkeratotic capillary-venous malformations (HCCVMs) are rare cutaneous lesions that occur in a small subgroup of patients with cerebral capillary malformation (CCM). CCMs cause neurological problems that range from headaches to life-threatening intracranial bleeding. CCMs and HCCVMs have a similar histopathological appearance of dilated capillary-venous channels. Genetic linkage of inherited CCMs has been established to three chromosomal loci, 3q25. 2-27, 7p13-15 and 7q21-22. The first mutations were identified in the CCM1 gene (located on 7q21-22), which encodes KRIT1 protein (KREV1 interaction trapped 1), presumably a membrane-bound protein with signalling activity. Although KRIT1 is known to interact with KREV1/RAP1A, a Ras-family GTPase, the exact function of KRIT1 in the formation of cerebral capillaries and veins is poorly understood. In this study, we screened five families with CCM for mutations in the KRIT1 gene. In one of the families, CCMs co-segregated with HCCVMs. We identified a KRIT1Delta(G103)mutation in this family, suggesting that this rare form of the condition is also caused by mutations in the CCM1 gene and that KRIT1 is probably important for cutaneous vasculature. Interestingly, this deletion introduces the earliest stop codon among identified mutations, suggesting a possible correlation between the molecular alteration and the cutaneous phenotype. Another novel mutation, KRIT1(IVS2+2(T-->C)), was found in a family with only cerebral capillary-venous malformations.

Complications of systemic corticosteroid therapy for problematic hemangioma

Systemic corticosteroid therapy has been used to treat hemangiomas for 30 years; yet, there are no studies of possible complications. We reviewed the database of the Vascular Anomalies Center at the Boston Children's Hospital and gathered information on short- and long-term side effects in children who were given systemic corticosteroids for problematic hemangiomas. In addition, a questionnaire regarding early and late consequences was sent to the families of children who were treated with corticosteroids from 1983 to 1997. Of 300 patients with hemangiomas, 80 children were identified as having received a full course of systemic corticosteroids for problematic tumors. Complete data were collected on 62 of these children. The response rate to the questionnaire was 78 percent (n = 62 of 80). The initial dose of corticosteroid varied from 2 to 3 mg/kg/ day. Duration of therapy ranged from 2 to 21 months (mean, 7.9 months; median, 6.5 months). The follow-up interval from the cessation of therapy ranged from 6 months to 15 years (mean, 4 years; median, 3 years). Short-term complications included cushingoid facies (n = 44; 71 percent), personality changes (n = 18; 29 percent), gastric irritation (n = 13; 21 percent), fungal (oral or perineal) infection (n = 4; 6 percent), and diminished gain of height (n = 22; 35 percent) and weight (n = 26; 42 percent). A total of 91 percent of children who had diminished gain of height (n = 20) returned to their pretreatment growth curve for height by 24 months of age. One child, who was treated at another institution with a dose of 20 mg/kg/day for 6.5 months that was slowly tapered over 18 months, was petite 6 years after ending therapy. Another child treated with an initial dose of 2 mg/kg/day for 5 months was smaller than predicted at the age of 6 years, but she was born prematurely and was on ventilatory support for respiratory distress. Three children treated with the standard dose and duration were at a low percentile for weight 4, 5, and 10 years after the cessation of therapy. Statistical analysis showed a correlation between diminished gain of height with duration of therapy and age at initiation of treatment. One child had corticosteroid myopathy that resolved with cessation of therapy. We found no evidence for immunologic suppression, i.e., there was no increase in the number of bacterial infections during corticosteroid administration. In conclusion, systemic corticosteroids can be safely given to treat endangering hemangiomas in infants at doses of 2 to 3 mg/kg/day, which are slowly tapered and stopped before the age of 1 year. Short-term side effects were minor and transient, and no serious long-term complications occurred.

A gene for inherited cutaneous venous anomalies ("glomangiomas") localizes to chromosome 1p21-22

Venous malformations (VMs) are localized defects of vascular morphogenesis. They can occur in every organ system, most commonly in skin and muscle. They can cause pain and bleeding, and in some critical locations they can be life threatening. Usually venous anomalies occur sporadically, but families with dominant inheritance have been identified. Using linkage analysis, we have established in earlier reports that some families with inherited VMs show linkage to chromosome 9p21; the mutation causes ligand-independent activation of an endothelial cell-specific receptor tyrosine kinase, TIE-2. Here we show that VMs with glomus cells (known as "glomangiomas"), inherited as an autosomal dominant trait in five families, are not linked to 9p21 but, instead, link to a new locus, on 1p21-p22, called "VMGLOM" (LOD score 12.70 at recombination fraction.00). We exclude three known positional candidate genes, DR1 (depressor of transcription 1), TGFBR3 (transforming growth factor-beta receptor, type 3), and TFA (tissue factor). We hypothesize that cutaneous venous anomalies (i.e., glomangiomas) are caused by mutations in a novel gene that may act to regulate angiogenesis, in concert with the TIE-2 signaling pathway.

Molecular Basis of Vascular Anomalies

Vascular anomalies comprise a heterogeneous group of disorders that are divided into tumors (hemangiomas) and malformations. Recent advances in biomedical research provide insights into the molecular basis of these disorders and a deeper understanding of vascular morphogenesis. In the future, this emerging knowledge will contribute to novel ways to treat vascular anomalies and to regulate pathologic angiogenesis.

Vascular dysmorphogenesis caused by an activating mutation in the receptor tyrosine kinase TIE2

Venous malformations (VMs), the most common errors of vascular morphogenesis in humans, are composed of dilated, serpiginous channels. The walls of the channels have a variable thickness of smooth muscle; some mural regions lack smooth muscle altogether. A missense mutation resulting in an arginine-to-tryptophan substitution at position 849 in the kinase domain of the receptor tyrosine kinase TIE2 segregates with dominantly inherited VM in two unrelated families. Using proteins expressed in insect cells, we demonstrate that the mutation results in increased activity of TIE2. We conclude that an activating mutation in TIE2 causes inherited VMs in the two families and that the TIE2 signaling pathway is critical for endothelial cell-smooth muscle cell communication in venous morphogenesis.

Hepatic vascular anomalies in infancy: a twenty-seven-year experience

OBJECTIVE

Infantile hemangioma and arteriovenous malformation (AVM) of the liver have a similar presentation but a different natural history, and therefore require different treatment. This study was undertaken to clarify differential diagnosis and management of these two biologically distinct vascular disorders.

STUDY DESIGN

We retrospectively analyzed the records of 43 children with hepatic vascular anomalies treated during the past 27 years.

RESULTS

Ninety percent were hemangiomas (n = 39); 10% were AVM (n = 4). Infants with AVM or large solitary hemangioma had hepatomegaly, congestive heart failure, and anemia as presenting symptoms at birth. Multiple hepatic hemangiomas manifested at 1 to 16 weeks of age with the same clinical triad, plus multiple cutaneous lesions (19/23). The mortality rate after treatment of hepatic AVM was 50% (2/4). The mortality rates after treatment of liver hemangiomas were as follows: resection of solitary lesions, 20% (2/10); embolization, 43% (3/7); corticosteroids, 30% (3/10); and interferon alfa-2a, 15% (2/13).

CONCLUSION

Solitary hepatic hemangioma cannot always be distinguished from hepatic AVM without radiologic studies. Multiple hepatic hemangiomas are differentiated from hepatic AVM by coexistence of multiple cutaneous hemangioma and by radiologic imaging. We recommend combined embolization and surgical resection for hepatic AVM and for solitary symptomatic hemangioma, if drug therapy fails. Pharmacologic treatment is used for symptomatic multiple liver hemangiomas. Embolization allows interim control of heart failure. A decreased mortality rate after interferon alfa-2a therapy is encouraging.

E-selectin is present in proliferating endothelial cells in human hemangiomas

E-selectin, an endothelial-cell-specific leukocyte adhesion molecule, may also function in angiogenesis. To investigate its role in a noninflammatory angiogenic disease, E-selectin was analyzed by immunohistochemistry in specimens of proliferative phase and involutive phase hemangiomas. Hemangioma is an endothelial cell tumor of capillary blood vessels that grows rapidly during infancy and regresses spontaneously during childhood. E-selectin expression was high in proliferative phase specimens and was co-localized with dividing microvascular endothelial cells. Relative to the number of blood vessels, E-selectin declined significantly in involutive phase specimens demonstrating that E-selectin correlates with angiogenesis in the tumors. E-selectin was not detected in quiescent endothelium but was co-localized in dividing microvascular endothelial cells in placenta and neonatal foreskin, two tissues with ongoing growth of microvessels. These in vivo studies support the hypothesis that E-selectin functions in angiogenesis and suggest that E-selectin may be a marker for proliferating endothelium.

Congenital hemangioma: evidence of accelerated involution

OBJECTIVE

To study the course of hemangiomas that proliferate in utero, are fully grown at birth, and begin to regress during early infancy.

DESIGN

We analyzed retrospectively 31 infants with congenital hemangioma seen at Tarnier-Cochin Hospital (Paris) and Children's Hospital (Boston). Diagnosis was made by clinical and radiologic examination and, if necessary, by biopsy. Age, gender, location, appearance, and evolution were noted for each infant.

RESULTS

Only 3 of 23 congenital hemangiomas were diagnosed in utero by ultrasonography. The three most common morphologic forms were raised violaceous tumor with ectatic veins (n = 8), raised grayish tumor with multiple tiny telangiectasias, surrounded by a pale halo (n = 8), and flat infiltrative tumor with violaceous overlying skin (n = 5). Two congenital hemangiomas had associated thrombocytopenic coagulopathy (Kasabach-Merritt phenomenon). All the untreated congenital hemangiomas (n = 24) regressed by the time the infants were 14 months of age, leaving either atrophic skin or extra skin. Seven congenital hemangiomas required therapy for complications: three tumors responded to systemic corticosteroid administration and four were resected.

CONCLUSION

Hemangiomas can proliferate in utero and manifest as fully developed tumors at birth. These congenital hemangiomas can regress rapidly. This phenomenon raises new questions about the pathogenesis of this tumor.

Congenital fibrosarcoma masquerading as congenital hemangioma: report of two cases

The authors report on two infants who had large congenital fibrosarcomas that initially were believed to be hemangiomas. Although hemangioma and congenital fibrosarcoma can have a similar presentation, their treatment is dissimilar. The authors review the anatomic findings, hematologic differences, and radiological clues that can help to differentiate congenital fibrosarcoma from congenital hemangioma.

Not all hemangiomas look like strawberries: uncommon presentations of the most common tumor of infancy

The typical appearance of cutaneous hemangiomas of infancy is well known. We studied unusual manifestations of this common tumor. We reviewed over 500 hemangiomas in the registry of the Vascular Anomalies Program at Boston Children's Hospital. We found four uncommon morphologic variations: deep hemangiomas with normal overlying skin (n = 12); macular hemangiomas with a port-wine stainlike appearance (n = 6); bossed hemangiomas with telangiectasia and peripheral pallor (n = 5); and hemangiomas with persistent fast flow (n = 3). Deep and superficial (macular) varieties regressed at a normal rate. Telangiectatic (bossed) hemangiomas, however, involuted rapidly, usually before 1 year of age. Hemangiomas with persistent fast flow required either resection or sclerotherapy for complications in early childhood.

A gene for familial venous malformations maps to chromosome 9p in a second large kindred

Venous malformations are a common form of vascular anomaly that cause pain and disfigurement and can be life threatening if they involve critical organs. They occur sporadically or in a familial form, where multiple lesions are usually present. We have identified a large kindred showing autosomal dominant inheritance of venous malformations. Using this family we confirm linkage of a familial form of venous malformations to chromosome 9p. We suggest that blue rubber bleb naevus syndrome can be considered a particular manifestation of this form of familial venous malformations. The candidate region for this gene encompasses the interferon gene cluster and the MTS1 (p16) tumour suppressor gene.

Assignment of a locus for dominantly inherited venous malformations to chromosome 9p

Venous malformation is the most common type of vascular anomaly. Depending upon size and location, these slow-flow anomalies may cause pain, anatomic distortion, or threaten life. Most venous malformations occur sporadically and present as solitary lesions. They also occur in several syndromes, some of which demonstrate Mendelian inheritance. We have mapped the locus for an autosomal dominant disorder in a three generation family that manifests as multiple cutaneous and mucosal venous malformations. This locus lies within a 24 cM interval on chromosome 9p, defined by the markers D9S157 and D9S163. The alpha and beta interferon gene cluster and the putative tumor suppressor genes MTS1 and MTS2 are also in this region. Characterization of the gene responsible for this disorder should yield insights into the precise pathogenic mechanisms for venous malformations.