RASA1 mutations and associated phenotypes in 68 families with capillary malformation-arteriovenous malformation

Capillary malformation-arteriovenous malformation (CM-AVM) is an autosomal-dominant disorder, caused by heterozygous RASA1 mutations, and manifesting multifocal CMs and high risk for fast-flow lesions. A limited number of patients have been reported, raising the question of the phenotypic borders. We identified new patients with a clinical diagnosis of CM-AVM, and patients with overlapping phenotypes. RASA1 was screened in 261 index patients with: CM-AVM (n = 100), common CM(s) (port-wine stain; n = 100), Sturge-Weber syndrome (n = 37), or isolated AVM(s) (n = 24). Fifty-eight distinct RASA1 mutations (43 novel) were identified in 68 index patients with CM-AVM and none in patients with other phenotypes. A novel clinical feature was identified: cutaneous zones of numerous small white pale halos with a central red spot. An additional question addressed in this study was the "second-hit" hypothesis as a pathophysiological mechanism for CM-AVM. One tissue from a patient with a germline RASA1 mutation was available. The analysis of the tissue showed loss of the wild-type RASA1 allele. In conclusion, mutations in RASA1 underscore the specific CM-AVM phenotype and the clinical diagnosis is based on identifying the characteristic CMs. The high incidence of fast-flow lesions warrants careful clinical and radiologic examination, and regular follow-up.

Meso-Rex shunt for immediate portal revascularization in pediatric liver transplantation: first report

We describe the case of a 13-month-old girl transplanted for biliary atresia with PV hypoplasia. She received the left liver lobe of her mother and presented intraoperative portal thrombosis. Because of technical reasons, the opportunity to have conventional PV reconstruction using the donor left PV stump was lost. Immediate conversion to a meso-Rex shunt, using the recipient jugular vein as a bridge between the superior mesenteric vein and the graft Rex recessus, allowed excellent portal revascularization of the transplant. We suggest that synchronous meso-Rex shunt may constitute a valid alternative to truncal PV anastomosis during pediatric LT.

Sonographic assessment of the retroperitoneal position of the third portion of the duodenum: an indicator of normal intestinal rotation

BACKGROUND

The diagnosis of intestinal malrotation is based on an upper gastrointestinal contrast series (UGI), which is considered the imaging reference standard. It may however be challenging even for experienced paediatric radiologists.

OBJECTIVE

The purpose of this study was to demonstrate the agreement between UGI and US in assessing the position of the third portion of the duodenum (D3) and to show that a retroperitoneal duodenum indicates normal forgut rotation.

MATERIALS AND METHODS

In a prospective study, US assessment of the duodenum and the superior mesenteric vessels was performed in consecutive children who were referred for clinically indicated UGI at a single institution.

RESULTS

Eighty-five children, 5 months to 14 years old, were studied. In 82/85 (96%), both US and UGI suggested normal forgut rotation. In three children, US demonstrated a normal position of the D3 whereas UGI showed an abnormal position of the duodeno-jejunal junction.

CONCLUSION

US is a non-invasive, easily performed technique for excluding malrotation. UGI may be reserved for situations where US does not demonstrate a normal position of the D3.

Development of renal and iliac aneurysms in a child with generalized infantile myofibromatosis

Infantile myofibromatosis is a rare disorder characterized by the formation of tumors in the skin, soft tissues, bone, and viscera. We report the case of a 3-week-old girl who presented with severe hypertension due to generalized infantile myofibromatosis including renal involvement. The infant was treated by chemotherapy and showed progressive regression of the tumors. However, her evolution was marked by the development of aneurismal dilations of the renal and iliac arteries as observed in fibromuscular dysplasia. We discuss the possibility of a link between these two mesenchymal disorders.

Elevated D-dimer level in the differential diagnosis of venous malformations

OBJECTIVE

To evaluate if elevated D-dimer level is specific for venous malformations (VMs) and thus useful for differential diagnosis, which can be problematic even in specialized interdisciplinary centers. Localized intravascular coagulopathy, characterized by elevated D-dimer levels, has been observed in approximately 40% of patients with VMs.

DESIGN

Prospective convenience sample accrued from 2 interdisciplinary sites.

SETTING

Two interdisciplinary centers for vascular anomalies in Brussels, Belgium, and Caen, France

PARTICIPANTS

The study population comprised 280 patients with clinical data, Doppler ultrasonograms (for 251 patients), and coagulation parameter measurements. Main Outcome Measure Measurement of D-dimer levels.

RESULTS

A VM was diagnosed in 195 of 280 patients (69.6%), and 83 of them had elevated D-dimer levels; the sensitivity of D-dimer dosage was 42.6% (95% confidence interval, 35.6%-49.5%). Among the 85 patients without VM, D-dimer levels were elevated only in 3 patients; the specificity of the dosage was 96.5% (95% confidence interval, 92.5%-100%).

CONCLUSIONS

Elevated D-dimer level is highly specific for VMs (pure, combined, or syndromic), and therefore this easy and inexpensive biomarker test should become part of the clinical evaluation of vascular anomalies. It can detect hidden VMs and help differentiate glomuvenous malformation (normal D-dimer levels) from other multifocal venous lesions. Elevated D-dimer level also differentiates a VM from a lymphatic malformation. Moreover, slow-flow Klippel-Trenaunay syndrome (capillaro-lymphatico-venous malformation with limb hypertrophy) can be distinguished from fast-flow Parkes Weber syndrome (capillary malformation with underlying multiple microfistulas and limb hypertrophy). For these reasons, D-dimer level measurement is a useful complementary tool for diagnosing vascular anomalies in everyday practice.

Parkes Weber syndrome, vein of Galen aneurysmal malformation, and other fast-flow vascular anomalies are caused by RASA1 mutations

Capillary malformation-arteriovenous malformation (CM-AVM) is a newly recognized autosomal dominant disorder, caused by mutations in the RASA1 gene in six families. Here we report 42 novel RASA1 mutations and the associated phenotype in 44 families. The penetrance and de novo occurrence were high. All affected individuals presented multifocal capillary malformations (CMs), which represent the hallmark of the disorder. Importantly, one-third had fast-flow vascular lesions. Among them, we observed severe intracranial AVMs, including vein of Galen aneurysmal malformation, which were symptomatic at birth or during infancy, extracranial AVM of the face and extremities, and Parkes Weber syndrome (PKWS), previously considered sporadic and nongenetic. These fast-flow lesions can be differed from the other two genetic AVMs seen in hereditary hemorrhagic telangiectasia (HHT) and in phosphatase and tensin homolog (PTEN) hamartomatous tumor syndrome. Finally, some CM-AVM patients had neural tumors reminiscent of neurofibromatosis type 1 or 2. This is the first extensive study on the phenotypes associated with RASA1 mutations, and unravels their wide heterogeneity.

Determinants of early atherosclerosis in obese children and adolescents

CONTEXT

Obesity in childhood is associated with an increased mortality due to cardiovascular (CV) diseases in adulthood, independent of adult weight. Recent studies in children indicate that the atherosclerosis process starts at an early age and is linked to obesity.

OBJECTIVE

The aim of the study was to investigate determinants of increased carotid intima-media thickness (IMT), an early marker of atherosclerosis, in obese children.

DESIGN

A total of 104 obese children [age, 12.7 +/- 0.2 yr; body mass index (BMI)-z-score, 2.8 +/- 0.7] underwent an oral glucose tolerance test. Fasting levels of glucose, insulin, C-reactive protein and adhesion molecules (sICAM, sVCAM, sE-selectin), lipid profile, adiponectin, and resistin were determined. IMT was measured by ultrasound. Insulin resistance was estimated by the homeostatic model assessment index. Baseline measurements of blood parameters were obtained from 93 nonobese children (age, 13.0 +/- 0.2 yr; BMI-z-score, -0.2 +/- 0.9), and IMT was measured in 23 other control children with similar characteristics.

RESULTS

Univariate analysis showed a significant positive correlation between IMT and relative BMI, the degree of systolic hypertension, fasting insulin levels, homeostatic model assessment-R index, and resistin concentrations, whereas an inverse correlation with adiponectin levels was found. No correlation was obtained between IMT and classical CV risk factors such as positive familial history of type 2 diabetes or precocious CV disease, visceral obesity, or the lipid profile. C-reactive protein and adhesion molecule levels were not associated with IMT in our obese population. When controlled for sex, Tanner stage, and relative BMI, only adiponectin levels remained an independent determinant of IMT.

CONCLUSION

Adiponectin more than conventional CV risk factors and inflammation status may be related to early atherosclerosis in obese children.

Early occurrence of hepatocellular carcinoma in biliary atresia treated by liver transplantation

A case of liver transplantation for HCC complicating BA in an eight-month old infant is reported. HCC in BA is extremely rare. Screening of AFP and ultrasonographic examination should be performed regularly in patients with secondary biliary cirrhosis for early detection of HCC.

2005 PRETEXT: a revised staging system for primary malignant liver tumours of childhood developed by the SIOPEL group

Over the last 15 years, various oncology groups throughout the world have used the PRETEXT system for staging malignant primary liver tumours of childhood. This paper, written by members of the radiology and surgery committees of the International Childhood Liver Tumor Strategy Group (SIOPEL), presents various clarifications and revisions to the original PRETEXT system.

Pyloric obstruction, duodenal dilatation, and extrahepatic cholestasis: a neonatal triad suggesting multiple intestinal atresias

Whereas physiologic jaundice constitutes a common finding in neonates, a few cases present with cholestatic jaundice owing to various pathologic conditions, including extrahepatic biliary obstruction. We report the case of a 2-day-old female neonate presenting with neonatal cholestasis, nonbilious vomiting with pyloric obstruction, and multiple intestinal atresias. A pathognomonic clinicoradiologic triad is described, based on clinical data, plain abdominal x-ray, and ultrasound examination.

Tumeurs et malformations vasculaires, classification anatomopathologique et imagerie

The understanding of vascular anomalies (vascular tumours and vascular malformations) was obscured, for a long time, by confusion and uncertainties in nosology and terminology. The International Society for the Study of Vascular Anomalies (ISSVA) recently adopted a classification scheme, clearly separating vascular tumours (hemangiomas of different types) which result from active cell proliferation, from vascular malformations, which are inborn defects in vascular morphogenesis. These two types of lesions have different clinical behaviour and require different diagnostic and therapeutic strategies. The most frequent vascular tumour is infantile hemangioma. Its clinical aspects and evolution are well-known. New data have been recently obtained concerning the phenotype of tumour cells and its histogenesis. Of the numerous new vascular tumours, which have been recently described, only the congenital hemangiomas, the vascular tumours associated with the Maffucci syndrome and the tumours that may be complicated by a profound thrombocytopenia (Kasabach and Merritt phenomenon) will be considered. Vascular malformations can be classified according to the vessel(s) types they are composed of. A classification table is presented, separating the malformations of vascular trunks from tissular malformations which are more intimately embedded in the surrounding tissues. The different syndromes associated with vascular anomalies take also place in this table. The clinical, imaging and histological aspects of the most frequent malformations (capillary, venous, lymphatic and arteriovenous) are presented. This classification intend to clarify the nosology and terminology of the complex field of vascular tumours and malformation and to offer a common language to the different physicians and specialists contributing, preferably with a interdisciplinary approach, to the diagnosis and treatment of these difficult lesions.

Pediatric diffusion tensor imaging: normal database and observation of the white matter maturation in early childhood

Recent advances in diffusion tensor imaging (DTI) have made it possible to reveal white matter anatomy and to detect neurological abnormalities in children. However, the clinical use of this technique is hampered by the lack of a normal standard of reference. The goal of this study was to initiate the establishment of a database of DTI images in children, which can be used as a normal standard of reference for diagnosis of pediatric neurological abnormalities. Seven pediatric volunteers and 23 pediatric patients (age range: 0-54 months) referred for clinical MR examinations, but whose brains were shown to be normal, underwent anatomical and DTI acquisitions on a 1.5 T MR scanner. The white matter maturation, as observed on DTI color maps, was described and illustrated. Changes in diffusion fractional anisotropy (FA), average apparent diffusion constant (ADC(ave)), and T2-weighted (T2W) signal intensity were quantified in 12 locations to characterize the anatomical variability of the maturation process. Almost all prominent white matter tracts could be identified from birth, although their anisotropy was often low. The evolution of FA, shape, and size of the white matter tracts comprised generally three phases: rapid changes during the first 12 months; slow modifications during the second year; and relative stability after 24 months. The time courses of FA, ADC(ave), and T2W signal intensity confirmed our visual observations that maturation of the white matter and the normality of its architecture can be assessed with DTI in young children. The database is available online and is expected to foster the use of this promising technique in the diagnosis of pediatric pathologies.

Outer diameter of the vermiform appendix: not a valid sonographic criterion for acute appendicitis in patients with cystic fibrosis

OBJECTIVE

We sought to investigate whether the outer diameter of the vermiform appendix on cross-sectional sonography is as reliable a criterion with which to confirm acute appendicitis in patients with cystic fibrosis as in those without cystic fibrosis.

CONCLUSION

The outer appendiceal diameter of 6 mm or more cannot be considered a reliable criterion for the diagnosis of acute appendicitis in patients with cystic fibrosis.

Planispheric multiplanar reformatted CT: a new method for evaluation of paediatric congenital spine abnormalities

We describe an original reconstruction method for spine CT performed in four patients with single or multiple congenital spine abnormalities. Conventional radiographic imaging is at the forefront of diagnosis and follow-up of congenital scoliosis, but is frequently difficult to interpret. Three-dimensional CT reconstruction facilitates visualization of complex anatomic structures, but does not give a reliable assessment of failures of segmentation. Mental three-dimensional reconstruction of the information displayed by classical multiplanar reformatted CT remains difficult. Planispheric reformatted imaging allows the visualization of all deformities in a single plane.

[Subacute osteomyelitis of the acetabulum]

A 15-months-old girl presented an excentration of the hip associated with a defect image of the acetabulum. Arthrography revealed a communication between the hip joint and the acetabular defect. Bacteriological specimens of the articular fluid were negative. The radiographic images were compatible with subacute osteomyelitis. Relative immobilization using an Atlanta abduction devise was undertaken. No medical treatment was prescribed for this adolescent who had received antibiotics for polymicrobial urinary tract infections and for pharyngitis prior to detection of the orthopedic disorder. Outcome was satisfactory with progressive filling of the acetabular defect but also with development of a subluxating coxa valga which required varus osteotomy of the femur. This case appears to illustrate a particular form of subacute osteomyelitis which is not described in earlier classifications.

The paediatric liver transplantation program at the Université catholique de Louvain

The Paediatric Liver Transplant Program at Saint-Luc University Clinics constitutes a substantial single centre experience, including 667 transplantations performed between March 1984 and April 2003, and the history of this program reflects the tremendous progress in this field since twenty years. Liver transplantation in children constitutes a considerable undertaking and its results depend on multiple, intermingled risk factors. An analysis of the respective impact of several surgical and immunological parameters on patient/graft outcome and allograft rejection after paediatric liver transplantation showed a significant learning curve effect as well as the respective impact of pre-transplant diagnosis on survival and of primary immunosuppression on the rejection incidence. The introduction of living related liver transplantation in 1993 not only permitted to provide access to liver replacement in as many as 74% more candidate recipients, but also resulted in better graft survival and reduced retransplantation rate. The results of a recent pilot study suggest that steroid avoidance is not harmful, and could even be beneficial for paediatric liver recipients, particularly regarding growth, and that combining tacrolimus with basiliximab (anti-CD25 chimeric monoclonal antibody) for steroid substitution appears to constitute a safe alternative in this context. The long-term issues represent the main future challenges in the field, including the possibility of a full rehabilitation through immunosuppression withdrawal and tolerance induction, the development of adolescence transplant medicine, and the risk of early atherogenesis in the adulthood.

Repeated detection of gas in the portal vein after liver transplantation: A sign of EBV-associated post-transplant lymphoproliferation?

A 1-yr-old child presented with intractable right sided pleural effusion and progressive clinical deterioration 3 weeks after liver transplantation for Alagille Syndrome. He had been treated successfully for severe acute rejection before. Ultrasound and Doppler mode studies repeatedly demonstrated air in the portal vein. Intra-abdominal and intra-thoracic lymphoproliferation was detected, and EBV virus load and serology were suggestive of primary EBV infection. Liver biopsy revealed blast-like infiltrates of B-cells, considered diagnostic for post-transplant lymphoproliferative disease. The disease resolved upon reduction of immunosuppression. We suggest that the detection of portal vein gas in pediatric liver transplant recipients beyond the early post-operative period may be a sign of intra-abdominal post-transplant lymphoproliferative disease.

[Choanal atresia: a retrospective study of 39 cases]

The purpose of this study was to investigate the clinical characteristics and the surgical management in patients with choanal atresia. We performed a retrospective study at the Saint-Luc University hospital, Brussels, between January 1988 and June 2000. Surgical corrections were performed using different approach (transnasal endoscopic, transpalatal) and different instrumentations (urethral sounds, laser nd-YAG, laser CO2, microdebrider). Portex endotracheal tubes were inserted as nasal stents in the vast majority of the patients with bilateral choanal atresia. Thirty-nine children with choanal atresia (22 unilateral and 17 bilateral) (9: M, 30: F) were studied. 38 of them were surgically managed. Based on clinical inspection and On CT-Scan, choanal atresia was defined as membranous for 4 patients, osseous for 6 and mixte for 29. Associated congenital anomalies were found in 22.7% of unilateral and in 70.5% of bilateral choanal atresia (Total: 43.5%). Of those children with bilateral choanal atresia, 75% were asymptomatic after four surgical procedures. In children with unilateral choanal atresia, 45% were asymptomatic after one surgical correction and 100% after three surgical corrections. Four patients were managed using an endoscopic endonasal approach with the microdebrider and showed no evidence of recurrence. Outcome analyses of factors that may influence the results of surgery are difficult to establish since many different surgical options were taken during this period. However, it seems that bilateral choanal atresia is associated with more surgical corrections before achieving a normal nasal breathing than unilateral choanal atresia. After this review, our current strategy regarding the choanal atresia will be to begin with the endoscopic endonasal approach using the microdebrider (stents if bilateral) and to propose the transpalatal approach in case of recurrence.

Living-related liver transplantation and vena cava reconstruction after total hepatectomy including the vena cava for hepatoblastoma

BACKGROUND

In most cases of total hepatectomy (TH) required for hepatoblastoma (HB), the retrohepatic inferior vena cava (IVC) has to be removed with the native liver for complete tumor excision. Because the liver graft procured by living donation has no IVC, a reconstruction of the recipient IVC is needed. We report our experience with living-related liver transplantation (LRLT) and IVC replacement in such cases.

METHODS

Between May 1998 and December 1999, four children underwent TH, including IVC and LRLT with IVC replacement for otherwise irresectable HB after chemotherapy (SIOPEL 2 and 3 protocols). IVC reconstruction used an allogenic iliac vein procured from a cadaveric donor (bank graft) in two cases and an internal jugular vein procured from the donor parent in two cases. Median age and weight at surgery were 17 months (range 10-60) and 9.6 kg (range 8.3-17.9).

RESULTS

In the living donors, there were two complications of the procurement: one intra-abdominal biliary collection and one subcutaneous abscess. In all four children, complete excision of the tumor could be achieved without any intra-operative complication. One patient died 5 months after LRLT due to lung metastases. Three patients were alive and well with no evidence of tumor recurrence 13-24 months after surgery. Reconstructed IVC was patent in two patients, and asymptomatic thrombosis occurred 2 years after operation in one patient.

CONCLUSION

Total hepatectomy including the retrohepatic IVC is not a technical obstacle to LRLT. Therefore, scheduled surgery, at the best time after chemotherapy, can be considered in all patients with otherwise irresectable HBs.

[Diagnosis and follow-up of a large intrahepatic portocaval fistula in a newborn]

Portocaval fistulas are rare and only exceptionally discovered in newborns. We report the case of a large portocaval fistula associated with portal hypoperfusion detected at Doppler US imaging in an otherwise asymptomatic 5 week old infant. The patient remained asymptomatic over the following two years. At that time, preoperative angiogram showed a normal portal venous system and the fistula was surgically closed. Postoperative US showed a normal and patent portal system, without evidence of portal hypertension.

Unusual evolution of an Epstein-Barr virus-associated leiomyosarcoma occurring after liver transplantation

We report the case of a child who developed, 2 yr after orthotopic liver transplantation (OLTx) for biliary atresia, a multi-focal hepatic tumor with lymphonodular metastases, identified as an Epstein-Barr virus (EBV)-associated leiomyosarcoma. Chemotherapy was given without tumor response. Subsequently, slow growth of the tumor was observed. Immunosuppression was tapered and stopped 9 yr after transplantation. At the present time, 12 yr after the discovery of the first hepatic lesions, the patient is alive and completely symptom-free, the abdominal masses are stable, and liver function tests are completely normal. Smooth muscle tumors are increasingly recognized in children with various immunodeficiencies occurring after organ transplantation. This unusual evolution of a clinically aggressive tumor into a stable disease after restoration of immunity confirms that the immune status of the patient is a crucial factor.