Juvenile Xanthogranuloma as Differential Diagnosis of a Vulvar Mass: A Case Report.

Vulvar masses in children are an unusual finding but their differential diagnosis is extensive. In case of solid masses, rhabdomyosarcoma (RMS) must always be considered due to the fact that it is the most common tumor in external genitals during childhood. However, RMS has a radiological appearance very similar to juvenile xanthogranuloma (JXG). We present a 16-month-old girl with a 2 cm solid mass on her left labia majora, with four overlying cutaneous papules. After imaging tests, an excisional biopsy was programmed due to high malignancy suspicion. Histopathology of the mass and one of the papules was diagnostic for JXG. After a 12-month follow-up, the patient shows no signs of relapse or complication. Deep JXG is an uncommon entity in childhood and exceptional in the genital area. Therefore, it must be included in the differential diagnosis of a solid vulvar mass, especially if accompanying yellowish xanthomatous cutaneous lesions are present.

Pediatric Inguinal Hernia Repair, Laparoscopic Versus Open Approach: A Systematic Review and Meta-Analysis of the Last 10-Year Evidence.

Aim: Since the first description of laparoscopic herniorrhaphy (LH), a lot of studies have compared outcomes between LH and open herniorrhaphy (OH) with inconsistent results. We designed this study to assess outcomes between both techniques now that pediatric surgeons have enough confidence with it. Methods: We performed a systematic review and meta-analysis of articles published in the last 10 years. Results: Twenty-seven articles reporting on 91,653 patients (26,920 LH and 64,733 OH) were included. No significant differences were found in overall operative time (OT) (P = .07). Subgroup analysis revealed significantly shorter OT for LH in unilateral (-8.87 minutes, P = .03) and bilateral hernias (-16.86 minutes, P = .004), but longer in unilateral hernias in females (+7.47 minutes, P = .006). Recurrence rate was similar (odds ratio [OR] 1.05, P = .66). Less complications were reported in LH (OR 0.51, P = .03). Contralateral patent processus vaginalis average rate was 39.61% and its closure reported a significant decrease of contralateral metachronous hernia (OR 0.11, P < .00001). Conclusion: Although OH is still considered the gold standard by some authors, LH has proven to be not only as safe as OH but also to have additional advantages that should make pediatric surgeons implement it in their daily practice and not in selected cases alone.

Management and results of thyroidectomies in pediatric patients with MEN 2 syndrome.

AIM OF THE STUDY: To evaluate the outcome of prophylactic thyroidectomies (PT) in patients with MEN 2 syndrome in a tertiary center. METHODS: A retrospective study was designed, including all patients with MEN 2 syndrome who underwent PT between 2000 and 2019. Demographics, gene mutation, postoperative complications and histopathological findings were registered. MAIN RESULTS: 30 patients were included (29 MEN 2A and 1 MEN 2B) with a median age at surgery time of 7.0 ± 3.2 years. Familiar history was present in all but 3 patients. A therapeutic thyroidectomy was performed in 2 patients due to evidence of medullary thyroid carcinoma (MTC, both were late diagnosis), and in the other 28 cases, a PT was performed. 8 patients had a RET mutation ranked as Moderate Risk (American Thyroid Association): median age at surgery was 7.2 ± 4.2 years, and histological findings were C-cell hyperplasia (n = 6) and no alterations (n = 2). 16 patients had a high risk mutation; median age at surgery time was 6.9 ± 2.8 years and histological findings were normal thyroid gland (n = 1), C Cell Hyperplasia (n = 8), microcarcinoma (n = 6), and MTC (n = 1). The mean hospital stay was 1.4 ± 0.68 days. No intraoperative complications or recurrent laryngeal nerve injuries were registered. 7 patients presented a transient hypoparathyroidism and 1 patient had permanent hypoparathyroidism. CONCLUSIONS: Early PT in patients with MEN 2 syndrome is a safe procedure when performed by an experienced team of Pediatric Surgeons and with a multidisciplinary approach. Early genetic analysis and familial counselling is essential to prevent the development of a MTC.

Ex-Utero Intrapartum Treatment (EXIT): indications and outcome in fetal cervical and oropharyngeal masses.

BACKGROUND: The "Ex-Utero Intrapartum Treatment" (EXIT) procedure allows to ensure fetal airway before completion of delivery and umbilical cord clamping while keeping uteroplacental circulation. Airway obstruction in fetal oropharyngeal and cervical masses can be life-threatening at birth. In those situations, controlled access to fetal airway performed by a trained multidisciplinary team allows safe airway management, while feto-maternal circulation is preserved. We aim to review the indications and outcome of the EXIT procedure in a case series of fetal cervical and oropharyngeal masses. METHODS: We have carried out a retrospective review of all patients with fetal cervical and oropharyngeal masses who underwent an EXIT procedure between 2008 and 2019. Variables evaluated included indication for EXIT, ultrasound and MRI findings, the need of amnioreduction, gestational age at EXIT, birth weight, complications, operative time, survival rate, pathological findings, and postnatal evolution. Five patients are included in this series. One additional case has already been published. RESULTS: The diagnosis were cervical teratoma (n = 1), epulis (n = 1) and lymphangioma (n = 3). Polyhydramnios was present in 2 patients, requiring amnioreduction in one of them. Mean gestational age at EXIT was 36-37 weeks (range, 34-38 weeks). Median EXIT time in placental support was 9 min (range, 3-22 min). Access to airway was successfully established in EXIT in all cases. All children born by EXIT are currently healthy and without complications. CONCLUSION: The localization and characteristics of the mass, its relationship to the airway, and the presence of polyhydramnios seem to be major factors determining indications for EXIT and clinical outcome.

First Experience with Fluorescence in Pediatric Laparoscopy.

Background The use of intraoperative fluorescence images with indocyanine green (ICG) has recently been described as an aid in decision-making during surgical procedures in adults. We present our first experiences with different laparoscopic procedures performed in children using ICG fluorescence images. Material and Method We have used ICG fluorescence imaging technique in varicocele ligation, two nephrectomies, cholecystectomy, and one case of aortocoronary fistula closure. All procedures were performed through a minimally invasive approach. A high definition camera equipped with a visible infrared light source and gray-scale vision technology was used. After injection of ICG before or during the laparoscopic procedure, precise identification of vascular anatomy and bile duct architecture were easily identified. Fluorescence helped to assess blood flow from the spermatic vessels, define the variability of renal vascularization, and determine the precise location of the aortocoronary fistula. Biliary excretion of the ICG allowed the definition of the biliary tract. Conclusion Fluorescein-assisted images allowed a clear definition of the anatomy and safe surgical maneuvers during surgical procedures. The ICG imaging system seems to be simple and safe. Larger and more specific studies are needed to confirm its applicability, expand its indications, and address its advantages and disadvantages.

Digital thoracic drainage: a new system to monitor air leaks in pediatric population.

INTRODUCTION: New digital thoracic drainage systems allow an objective measurement of air leakage. They have proven their usefulness in the postoperative thoracic surgery in adults, but there is little experience with its use in the pediatric population. The objective of our study is to analyze their safety and effectiveness in the postoperative period of the pediatric patients. METHOD: A prospective consecutive observational study was done. All patients submitted to pulmonary resection between 2011 and 2017 and in whom digital thoracic drainage system was used (Thopaz Chest Drain System, Medela, Switzerland) were prospectively enrolled in this study. We analyzed variables: duration of chest tube (CT), days of hospitalization and radiographs in the immediate postoperative period related to the presence of CT. This group was compared with a historical cohort of patients (from 2011 to 2015) with a pulmonary resection in whom the traditional thoracic drainage was used. For the statistical analysis, the Mann-Whitney U-Test was used for independent samples. RESULT: Twenty-six patients were included, Digital drainage system was used in13 patients and traditional drainage was used in 13 patients. The median age was 18 months (12 days-14 years). The mean number of days with the chest tube was 1.69 ±â€¯0.6 in digital drainage group versus 5.38 ±â€¯4 days in traditional drainage group (p < 0.05) The mean number of postoperative radiographs was 2.8 ±â€¯1.1 in digital drainage group versus 6.23 ±â€¯5.2 radiographs in traditional drainage group (p < 0.05). The average hospital stay in digital drainage group was 5.69 ±â€¯2.7 days versus 7 ±â€¯4.7 days in the traditional drainage group (p > 0.05). No complications related to the use of digital drainage group were registered. CONCLUSION: The digital thoracic drainage systems provide an objective measurement of air leakage, allowing early chest tube removal and decreasing the number of radiographs performed postoperatively. Its use in the pediatric population appears to be safe and potentially beneficial. LEVEL OF EVIDENCE: II.

Use of self-expanding nitinol stents in the pediatric management of refractory esophageal caustic stenosis.

BACKGROUND: The treatment of recurrent esophageal stricture secondary to the ingestion of a caustic agent is an arduous task. Self-expanding esophageal stents may be an alternative to repeated endoscopic esophageal dilations. CASE REPORT: We present the case of a two-year-old male with a severe and long esophageal stricture successfully treated by the combination of dilations and stent placement. After five months of serial pneumatic dilations, three self-expanding nitinol stents internally coated with silicone were introduced through a gastrostomy, covering the entire esophagus. The procedure was performed under endoscopic and radiological guidance. Three months later, the treatment was repeated with a single stent. A new stenosis in the proximal esophagus required surgical resection, and anastomosis followed by two pneumatic dilations for five months resulted in longer intervals where the patient was asymptomatic. DISCUSSION: The results obtained were satisfactory, allowing the patient to conserve and use his own esophagus. However, this is a unique case and the optimal maintenance time and withdrawal time of the stent must be determined.

Three-Dimensional Custom-Made Titanium Ribs for Reconstruction of a Large Chest Wall Defect.

Reconstruction of large chest wall defects always demand surgeons of having lots of means available (both materials and resourceful) to apply a cover to chest wall defects which can range from a few centimeters to the lack of a few entire ribs. In this study, we present the case of a teenager who suffered from a complete resection of three ribs because of Ewing sarcoma dependent on the sixth rib. Given the size of the defect, a multidisciplinary approach was chosen to provide rigid and soft tissue coverage and minimal functional and aesthetic impact. Custom-made titanium implants were designed based on three-dimensional computed tomography scan reconstruction. The surgical specimen via a left lateral thoracotomy (fifth, sixth, and seventh entire ribs) was resected, leaving a defect of 35 × 12 × 6 cm. A Gore-Tex patch (W. L. Gore & Associates, Arizona, United States) was placed and, after that, the implants were anchored to the posterior fragment of the healthy ribs and to the costal cartilage anteriorly. Finally, the surgical site was covered with a latissimus dorsi flap. The postoperative course was uneventful. After 9 months of follow-up, the patient has full mobility. This case shows that the implant of custom-made ribs, combined with other techniques, is a good surgical choice for reconstruction of large chest wall defects. The implant of custom-made ribs, combined with other techniques, is a good surgical choice for reconstruction of large chest wall defects.

How to set-up a program of minimally-invasive surgery for congenital heart defects.

BACKGROUND: Mid-line sternotomy is the commonest incision for cardiac surgery. Alternative approaches are becoming fashionable in many centres, amidst some reluctance because of learning curves and overall complexity. Our recent experience in starting a new program on minimally invasive pediatric cardiac surgery is presented. The rationale for a stepwise onset and the short-medium term results for a three-year span are displayed. METHODS: A three-step schedule is planned: First, an experienced surgeon (A) starts performing simple cases. Second, new surgeons (B, C, D, E) are introduced to the minimally invasive techniques according to their own proficiency and skills. Third, the new adopters are enhanced to suggest and develop further minimally invasive approaches. Two quality markers are defined: conversion rate and complications. RESULTS: In part one, surgeon A performs sub-mammary, axillary and lower mini-sternotomy approaches for simple cardiac defects. In part two, surgeons B, C, D and E are customly introduced to such incisions. In part three, new approaches such as upper mini-sternotomy, postero-lateral thoracotomy and video-assisted mini-thoracotomy are introduced after being suggested and developed by surgeons B, C and E, as well as an algorithm to match cardiac conditions and age/weight to a given alternative approach. The conversion rate is one out of 148 patients. Two major complications were recorded, none of them related to our alternative approach. Four minor complications linked to the new incision were registered. The minimally invasive to mid-line sternotomy ratio rose from 20% in the first year to 40% in the third year. CONCLUSIONS: Minimally invasive pediatric cardiac surgery is becoming a common procedure worldwide. Our schedule to set up a program proves beneficial. The three-step approach has been successful in our experience, allowing a tailored training for every new surgeon and enhancing the enthusiasm in developing further strategies on their own. Recording conversion-rates and complications stands for quality standards. A twofold increase in minimally invasive procedures was observed in two years. The short-medium term results after three years are excellent.

A Rare Complex Case of Congenital Umbilical Arteriovenous Malformation and Review of Literature.

Introduction Congenital umbilical arteriovenous malformations (AVMs) are extremely rare. We present the first case of congenital umbilical AVM with feeding arteries originating not only from abdominal but also from the mammary arteries. Case Report A 34-week gestational age newborn was transferred to our hospital with a supraumbilical murmur. Abdominal Doppler ultrasound (US) showed a large vascular AVM, with multiple feeding arteries and several venous drainage structures to the umbilical vein and also a persistent ductus venosus. She developed signs of heart failure on the 12th day of life. Computed tomography angiogram revealed an umbilical congenital AVM with feeding arteries originating from the external iliac, hypogastric, epigastric, and mammary arteries and a dilated umbilical vein draining the cluster. Also, a patent ductus venosus was observed. At 14 days of life, laparotomy was performed but due to the complexity of the feeding arteries of the AVM, complete exeresis was not performed, but only ligation of these arteries was made, to reduce the surgical risk. Conclusion To our knowledge, this is the first time that no complete excision was made but only ligation of the arteries. The infant was discharged home on postoperative day 14 being asymptomatic. Follow-up Doppler US showed thrombosed vascular structures.

Identification of different mechanisms leading to PAX6 down-regulation as potential events contributing to the onset of Hirschsprung disease.

Hirschsprung disease (HSCR) is attributed to a failure of neural crest derived cells to migrate, proliferate, differentiate or survive in the bowel wall during embryonic Enteric Nervous System (ENS) development. This process requires a wide and complex variety of molecules and signaling pathways which are activated by transcription factors. In an effort to better understand the etiology of HSCR, we have designed a study to identify new transcription factors participating in different stages of the colonization process. A differential expression study has been performed on a set of transcription factors using Neurosphere-like bodies from both HSCR and control patients. Differential expression levels were found for CDYL, MEIS1, STAT3 and PAX6. A significantly lower expression level for PAX6 in HSCR patients, would suit with the finding of an over-representation of the larger tandem (AC)m(AG)n repeats within the PAX6 promoter in HSCR patients, with the subsequent loss of protein P300 binding. Alternatively, PAX6 is a target for DNMT3B-dependant methylation, a process already proposed as a mechanism with a role in HSCR. Such decrease in PAX6 expression may influence in the proper function of signaling pathways involved in ENS with the confluence of additional genetic factors to the manifestation of HSCR phenotype.

EXIT procedure in twin pregnancy: a series of three cases from a single center.

BACKGROUND: Indications for the ex utero intrapartum therapy (EXIT) procedure have evolved and nowadays in addition to secure the airway, obtain vascular access, administer surfactant and other resuscitation medications, EXIT is used to resect cervical or thoracic masses, for extracorporeal membrane circulation (ECMO) cannulation, as well as to rescue maximum intra-thoracic space for ventilation of the remaining functional lung tissue or in cases in which resuscitation of the neonate may be compromised. EXIT procedure in twin pregnancy has been rarely reported and some doubts have been raised about its strategy and safety in such cases. METHODS: We reviewed the medical records of 3 twin pregnancy cases where the EXIT procedure have been performed in our center. RESULTS: The mean gestational age at EXIT procedure was 34 + 4 weeks. In two out the three EXIT procedures, the affected twin was delivered first. The average time on placental bypass was 9 minutes. There were no fetal or maternal complications related to the EXIT procedure. All newborns are currently doing well. CONCLUSION: In twin pregnancies, prenatal diagnosis combined with the EXIT procedure permits the formulation of a controlled delivery strategy to secure both newborns outcome. In those pregnancies, if intervention can be accomplished without compromise of the normal twin, EXIT can be considered. Our results support that EXIT procedure, if properly planned, safely provides a good outcome for both the fetuses as well as the mother.

Involvement of DNMT3B in the pathogenesis of Hirschsprung disease and its possible role as a regulator of neurogenesis in the human enteric nervous system.

PURPOSE: Hirschsprung disease (OMIM 142623) is a neurocristopathy attributed to a failure of cell proliferation or migration and/or failure of the enteric precursors along the gut to differentiate during embryonic development. Although some genes involved in this pathology are well characterized, many aspects remain poorly understood. In this study, we aimed to identify novel genes implicated in the pathogenesis of Hirschsprung disease. METHODS: We compared the expression patterns of genes involved in human stem cell pluripotency between enteric precursors from controls and Hirschsprung disease patients. We further evaluated the role of DNMT3B in the context of Hirschsprung disease by inmunocytochemistry, global DNA methylation assays, and mutational screening. RESULTS: Seven differentially expressed genes were identified. We focused on DNMT3B, which encodes a DNA methyltransferase that performs de novo DNA methylation during embryonic development. DNMT3B mutational analysis in our Hirschsprung disease series revealed the presence of potentially pathogenic mutations (p.Gly25Arg, p.Arg190Cys, and p.Gly198Trp). CONCLUSION: DNMT3B may be regulating enteric nervous system development through DNA methylation in the neural crest cells, suggesting that aberrant methylation patterns could have a relevant role in Hirschsprung disease. Moreover, the synergistic effect of mutations in both DNMT3B and other Hirschsprung disease-related genes may be contributing to a more severe phenotype in our Hirschsprung disease patients.

The relationship between the site of metastases and outcome in children with stage IV Wilms Tumor: data from 3 European Pediatric Cancer Institutions.

The aim of this study was to analyze in detail the site of metastasis of stage 4 Wilms tumor (WT) and its correlation with outcome. The databases from 3 major European pediatric cancer institutions were screened for children with WT between 1994 and 2011. Of 208 children identified, 31 (14.9%) had metastases at diagnosis. The lung was affected in 29 children (93.5%) and the liver in 6 children (19.4%). Twenty-seven children (87.1%) had metastases isolated to 1 organ, with the lung being the most common site (80.7%). Five-year overall survival was significantly better in those children with distant disease in either lung or liver (95.8%) compared with those affected in both lung and liver (57.1%, P=0.028). Further, prognostic markers were the response of metastases to preoperative chemotherapy (P=0.0138), high-risk histology (P=0.024), and local stage (P=0.026). Five-year overall survival was 82.1% and 5-year event-free survival was 67.9%. The overall follow-up time was 74.1 and 87.2 (2 to 151) months among survivors, and the treatment-related complication rate was 16.7%. In conclusion, in our series of stage 4 WT, prognosis was excellent if histology was favorable, metastatic disease was isolated to either lungs or liver, and if metastases responded to preoperative chemotherapy.

Mutational spectrum of semaphorin 3A and semaphorin 3D genes in Spanish Hirschsprung patients.

Hirschsprung disease (HSCR, OMIM 142623) is a developmental disorder characterized by the absence of ganglion cells along variable lengths of the distal gastrointestinal tract, which results in tonic contraction of the aganglionic colon segment and functional intestinal obstruction. The RET proto-oncogene is the major gene associated to HSCR with differential contributions of its rare and common, coding and noncoding mutations to the multifactorial nature of this pathology. In addition, many other genes have been described to be associated with this pathology, including the semaphorins class III genes SEMA3A (7p12.1) and SEMA3D (7q21.11) through SNP array analyses and by next-generation sequencing technologies. Semaphorins are guidance cues for developing neurons implicated in the axonal projections and in the determination of the migratory pathway for neural-crest derived neural precursors during enteric nervous system development. In addition, it has been described that increased SEMA3A expression may be a risk factor for HSCR through the upregulation of the gene in the aganglionic smooth muscle layer of the colon in HSCR patients. Here we present the results of a comprehensive analysis of SEMA3A and SEMA3D in a series of 200 Spanish HSCR patients by the mutational screening of its coding sequence, which has led to find a number of potentially deleterious variants. RET mutations have been also detected in some of those patients carrying SEMAs variants. We have evaluated the A131T-SEMA3A, S598G-SEMA3A and E198K-SEMA3D mutations using colon tissue sections of these patients by immunohistochemistry. All mutants presented increased protein expression in smooth muscle layer of ganglionic segments. Moreover, A131T-SEMA3A also maintained higher protein levels in the aganglionic muscle layers. These findings strongly suggest that these mutants have a pathogenic effect on the disease. Furthermore, because of their coexistence with RET mutations, our data substantiate the additive genetic model proposed for this rare disorder and further support the association of SEMAs genes with HSCR.

Comprehensive analysis of NRG1 common and rare variants in Hirschsprung patients.

Hirschsprung disease (HSCR, OMIM 142623) is a developmental disorder characterized by the absence of ganglion cells along variable lengths of the distal gastrointestinal tract, which results in tonic contraction of the aganglionic gut segment and functional intestinal obstruction. The RET proto-oncogene is the major gene for HSCR with differential contributions of its rare and common, coding and noncoding mutations to the multifactorial nature of this pathology. Many other genes have been described to be associated with the pathology, as NRG1 gene (8p12), encoding neuregulin 1, which is implicated in the development of the enteric nervous system (ENS), and seems to contribute by both common and rare variants. Here we present the results of a comprehensive analysis of the NRG1 gene in the context of the disease in a series of 207 Spanish HSCR patients, by both mutational screening of its coding sequence and evaluation of 3 common tag SNPs as low penetrance susceptibility factors, finding some potentially damaging variants which we have functionally characterized. All of them were found to be associated with a significant reduction of the normal NRG1 protein levels. The fact that those mutations analyzed alter NRG1 protein would suggest that they would be related with HSCR disease not only in Chinese but also in a Caucasian population, which reinforces the implication of NRG1 gene in this pathology.

Surgical management of Wilms tumor with intravascular extension: a single-institution experience.

The purpose of this study was to retrospectively analyze the clinical presentation, treatment, and outcomes of children with Wilms tumor (WT) and intravascular extension who were treated at a single institution. A retrospective review was conducted of medical records of all children with Wilms tumor and intravascular extension treated at Virgen del Rocio Children's Hospital between 1992 and 2010. Seven patients (median age 3.4 years, range 2-8.1 years) were identified. At diagnosis, 6 of the 7 patients (85.7%) presented with tumor thrombus that reached the right atrium (RA) and 1 patient with infrahepatic inferior vena cava (IVC) thrombus. All patients received neoadjuvant chemotherapy (SIOP 2001 protocol) with vincristine, doxorubicin, and actinomycin D. Regression of the intravascular extension of the tumor was documented in all patients. Postchemotherapy level of extension was suprahepatic IVC in 1 patient, infrahepatic IVC in 2 patients, renal vein (RV) in 1 patient, and RA in 3 patients. Nephrectomy and thrombectomy were performed in all cases, requiring cardiopulmonary bypass for the 4 patients who presented with suprahepatic IVC and RA thrombus. The other 3 patients with infrahepatic IVC and RV involvement underwent cavotomy and thrombus extraction. Computed tomography, ultrasonography, and echocardiography were used for diagnosis and follow-up. All patients remain disease-free with a median follow-up of 6.3 years (range, 2-19 years). Neoadjuvant chemotherapy for WT with intravascular extension may facilitate the resection by decreasing the extent of the tumor thrombus. Cardiopulmonary bypass is indicated for suprahepatic IVC and RA involvement. Accurate diagnostic imaging is necessary.

Association of X-linked hydrocephalus and Hirschsprung disease: report of a new patient with a mutation in the L1CAM gene.

X-linked hydrocephalus (XLH) has an incidence of 1/30,000 male births and is characterized by intellectual disability, spastic paraplegia, adducted thumbs, and agenesis of corpus callosum, and/or corticospinal tract. The great proportion of cases is ascribed to loss of function mutations of L1CAM gene. Hirschsprung disease (HSCR) is characterized by the absence of ganglion cells in the submucosal and myenteric plexuses along a variable portion of the intestinal tract and has incidence of about 1/5,000. Although with several genes involved in its pathogenesis, the major HSCR gene is the RET proto-oncogene. To date only a few patients have been reported with both phenotypes and mutations in the L1CAM gene. In this report, we describe a new patient with concurrent XLH and HSCR. L1CAM mutational screening showed the presence of the G698R hemizygous mutation, which is a deleterious substitution affecting a key residue necessary for the correct folding of the protein. Moreover, the patient also carried the transcriptional enhancer RET mutation (c.73 + 9277T > C) in heterozygosis. We speculate that both the RET enhancer variant, and the L1CAM mutation may act in combination to produce the enteric phenotype, probably with the participation of other still unidentified molecular events. While it is obvious that additional studies are necessary to further delineate the association between XLH and HSCR in the presence of L1CAM mutations, the documentation of this new patient reinforces the role of this gene acting either in a direct or indirect way in the pathogenesis of Hirschsprung disease.

Expression of PROKR1 and PROKR2 in human enteric neural precursor cells and identification of sequence variants suggest a role in HSCR.

BACKGROUND: The enteric nervous system (ENS) is entirely derived from neural crest and its normal development is regulated by specific molecular pathways. Failure in complete ENS formation results in aganglionic gut conditions such as Hirschsprung's disease (HSCR). Recently, PROKR1 expression has been demonstrated in mouse enteric neural crest derived cells and Prok-1 was shown to work coordinately with GDNF in the development of the ENS. PRINCIPAL FINDINGS: In the present report, ENS progenitors were isolated and characterized from the ganglionic gut from children diagnosed with and without HSCR, and the expression of prokineticin receptors was examined. Immunocytochemical analysis of neurosphere-forming cells demonstrated that both PROKR1 and PROKR2 were present in human enteric neural crest cells. In addition, we also performed a mutational analysis of PROKR1, PROKR2, PROK1 and PROK2 genes in a cohort of HSCR patients, evaluating them for the first time as susceptibility genes for the disease. Several missense variants were detected, most of them affecting highly conserved amino acid residues of the protein and located in functional domains of both receptors, which suggests a possible deleterious effect in their biological function. CONCLUSIONS: Our results suggest that not only PROKR1, but also PROKR2 might mediate a complementary signalling to the RET/GFRα1/GDNF pathway supporting proliferation/survival and differentiation of precursor cells during ENS development. These findings, together with the detection of sequence variants in PROKR1, PROK1 and PROKR2 genes associated to HSCR and, in some cases in combination with RET or GDNF mutations, provide the first evidence to consider them as susceptibility genes for HSCR.

Laparoscopic surgery in a rat model.

BACKGROUND: The rat is increasingly being used in laparoscopic research. Laparoscopic microsurgical training is critical in order to develop new surgical indications in pediatric patients. This report evaluates laparoscopic splenectomy and nephrectomy in a rat model. MATERIALS AND METHODS: A Wistar rat (weight between 250 and 400 g) was placed in the supine position. Inhaled 3% halothane anesthesia was administered. A Veress needle is inserted in the right-upper abdomen. After establishing a pneumoperitoneum of 3-4 mm Hg, a 2- or 5-mm trocar was placed, according to the procedure. A 2-mm 0-degree endoscope was used. Two additional 2- or 5-mm trocars were then placed. Laparoscopic splenectomy involved two-handed dissection, intracorporeal ligation, and the division of gastrosplenic attachments and hilar and short gastric vessels. Laparoscopic nephrectomy was done by intracorporeal ligation and division of the renal vessels and the ureter after mobilization of the kidney. RESULTS: Laparoscopic splenectomy was performed in 8 rats; laparoscopic nephrectomy was done in 4 rats. Operative time was 25-40 minutes for splenectomy and from 30 to 65 for nephrectomy. Postoperatively, 4 rats died from hemorrhage. No wound infections occurred at the port sites. CONCLUSIONS: Laparoscopic splenectomy and nephrectomy in an experimental rat model is technically feasible and may provide an excellent training model for pediatric minimally invasive surgery.