Conservative management of chylous ascites after oncological surgery for peripheral neuroblastic tumors in pediatric patients.

Chylous ascites may complicate the postoperative course of abdominal surgery mainly due to the iatrogenic disruption of the lymphatic channels during extensive retroperitoneal dissection. Sparse data are available regarding treatment; however, in many cases a recommended first-line treatment approach is by way of enteral feeding, consisting of a formula high in medium-chain triglycerides (MCTs) together with a complete total parenteral nutrition teamed with somatostatin (or an equivalent). Nonetheless, the ligation of chylous fistulae, together with the application of Fibrin glue, as well as the creation of peritoneal-venous shunts have also been documented. The aims of this study are to document incidence of postoperative chylous ascites following resection of abdominal peripheral neuroblastic tumors, evaluate efficacy of the management of chylous ascites, and investigate the main risk factors. A survey was carried out over a span of six years, from March 2010 to March 2016 at Giannina Gaslini Children's Hospital involving seventy-seven children with resections of peripheral neuroblastic tumors. Incidence rate of postoperative chylous ascites following a normal diet was 9% (n=7). Treatment using total parenteral nutrition with octreotide resulted in a complete recovery from chylous ascites within a 20 day period without recurrence. Length of operative time, nephrectomy, and the extension of lymphadenectomy were all significantly associated with a higher incidence of postoperative chylous ascites (p<0.05) which also lengthened hospital stay (p<0.05) and possibly delayed beginning adjuvant chemotherapy.

Search for pathogenetic variants of the SPRY2 gene in intestinal innervation defects.

SPRY2 is an inducible inhibitor of signalling mediated by tyrosine kinases receptors, whose targeting causes intestinal hyperganglionosis in mice. In this light, we have undertaken a mutational analysis of the SPRY2 gene in patients affected with intestinal neuronal dysplasia (IND), without detecting nucleotide changes in any of the 26 DNA samples analysed, with the exception of two already known polymorphic variants. A role of the SPRY2 gene in IND pathogenesis can be thus excluded.

Hirschsprung's disease, one of the most difficult diagnoses in pediatric surgery: a review of the problems from clinical practice to the bench.

PURPOSE: The diagnosis of Hirschsprung's disease (HSCR) should take place early in the neonatal period, because without an effective diagnosis and appropriate treatment, a considerable proportion of infants will go on to develop serious complications such as acute enterocolitis or toxic megacolon. Because no more than 10 % of HSCR cases have a late presentation with classical chronic constipation and megacolon, the clinician has to make a difficult, early diagnosis, which is the crux of the clinical problem. The aim of this review paper is to present all tools currently available to make a clear HSCR diagnosis and to discuss the problems facing the clinician and the pediatric surgeon in the correct identification of HSCR and of other intestinal dysganglionoses. METHODS: Based on the current state of knowledge and 24 years' personal experience in clinical practice and basic research in this field, I describe an algorithmic approach that enables clinicians and surgeons to rationalize and maximize the clarity of diagnosis through a complementary set of procedures and enzyme-histochemical reactions. RESULTS: Two innovative techniques, added to the protocol in the last four years, are described: the lyophilized HSCR diagnostic kit, and the one-trocar transumbilical laparoscopic intestinal full-thickness biopsy technique (OTTLB). CONCLUSION: The rational, algorithmic diagnostic pathway proposed in this review paper aims to optimize every diagnosis by the stepwise application of a complementary set of procedures and enzyme-histochemical reactions as they become appropriate. In the interests of simplifying genetic molecular diagnosis, I suggest the following guidelines: 1) only in cases of total colonic aganglionosis (TCA) is it advisable to carry out full RET mutation screening (the mutation rate is up to 70 %); and 2) all HSCR patients should be tested only for standard MEN2A and MTC mutations. If these are present, the patients should be followed up carefully with proper surveillance and biochemical testing of other susceptible family members as they are at risk of developing neuroendocrine tumors.

Neural crest neuroblasts can colonise aganglionic and ganglionic gut in vivo.

INTRODUCTION: Neural crest (NC) cells differentiate IN VITRO into neuroblasts, precursors of the enteric nervous system (ENS), when stimulated by specific agents. We developed a study aimed at establishing whether NC-derived neuroblasts can survive and colonise IN VIVO when injected into a recipient mouse gut. MATERIALS AND METHODS: The neuroblast precursors of the ENS were obtained from the vagal portion of the neural tubes of 296 CD-1 and GTROSA26 mouse embryos. The embryonic cells of GTROSA26 mice are identifiable through beta-galactosidase activity which allows recognition by blue staining. The host used in this study was the DOM/+ mouse, an animal model for Hirschsprung's disease (aganglionic megacolon). DOM/+ mouse pups (n = 43) received NC-derived cells inoculated into the seromuscular layer of the gut (33/43) or directly into the peritoneal abdominal cavity (10/43). RESULTS: All DOM/+ mice survived the procedure and were sacrificed after 7 or 14 days. Histochemical staining detected implanted cells in all mice. These showed specific myenteric colonisation into the aganglionic and ganglionic gut. CONCLUSION: The striking result of this study was the specific tropism of the injected NC-derived cells to target sites under the action of unknown chemotactic agents. This experimental procedure might represent a possible treatment option for specific forms of human ENS anomaly such as total intestinal aganglionosis.

[Molecular biology, basic research and diagnosis of Hirschsprung's disease]. / Molekularbiologie, Grundlagenforschung und Diagnose des Morbus Hirschsprung.

The proto-oncogene RET is the major gene responsible for Hirschsprung's disease (HSCR), with RET mutations also implied in different pathologies. A variety of mutations of the RET proto-oncogene have been detected in HSCR patients. Special attention should be paid to rare patients who carry mutations of one of the critical cysteine residues of these exons, known to predispose to MEN2A. In these cases, HSCR can be associated with the development of neuroendocrine tumors such as medullary thyroid carcinoma (MTC) or MEN2A, for which a prophylactic thyroidectomy is advisable in the presence of a tumor causing RET mutation. In combined MEN2A/HSCR families, RET gene testing, tumor screening and prophylactic thyroidectomy are indicated as in MEN2A. The multigenic origin of HSCR and the absence of a "standard" RET mutation associated with HSCR currently make a routine molecular diagnosis impossible.

Haplotypes of the human RET proto-oncogene associated with Hirschsprung disease in the Italian population derive from a single ancestral combination of alleles.

The RET proto-oncogene is the major gene involved in the complex genetics of Hirschsprung disease (HSCR), or aganglionic megacolon, showing causative loss-of-function mutations in 15-30% of the sporadic cases. Several RET polymorphisms and haplotypes have been described in association with the disease, suggesting a role for this gene in HSCR predisposition, also in the absence of mutations in the coding region. Finally, the presence of a functional variant in intron 1 has repeatedly been proposed to explain such findings. Here we report a case-control study conducted on 97 Italian HSCR sporadic patients and 85 population matched controls, using 13 RET polymorphisms distributed throughout the gene, from the basal promoter to the 3'UTR. Linkage disequilibrium and haplotype analyses have shown increased recombination between the 5' and 3' portions of the gene and an over-representation, in the cases studied, of two haplotypes sharing a common allelic combination that extends from the promoter up to intron 5. We propose that these two disease-associated haplotypes derive from a single founding locus, extending up to intron 19 and successively rearranged in correspondence with a high recombination rate region located between the proximal and distal portions of the gene. Our results suggests the possibility that a common HSCR predisposing variant, in linkage disequilibrium with such haplotypes, is located further downstream than the previously suggested interval encompassing intron 1.

Feasibility of perineal sagittal approaches in patients without anorectal malformations.

Perineal sagittal approaches (posterior sagittal anorectoplasty and anterior and posterior sagittal transanorectal approaches) allow complete anatomic exposure of the perineum and lower pelvis. Moreover, they reduce the risk of damaging important structures because the incision is led in the midline. Therefore, many surgeons have used these approaches to treat diseases other than anorectal malformations (ARM), including intestinal dysganglionosis, trauma, pseudohermaphroditism, presacral mass, and rectal duplication. The aim of this study was to describe a small series of patients operated on via these approaches at Gaslini Children's Hospital over a 5-year period. We retrospectively evaluated 10 patients consecutively operated on via a perineal sagittal approach, with or without sphincteric structure involvement, between January 1997 and December 2001. All of these patients were without ARM. Indications included retrorectal abscesses (two), iatrogenic anal canal stenosis (one), postinflammatory anal canal stenosis (one), internal anal sphincter neurogenic achalasia (one), female pseudohermaphroditism (one), benign sacrococcygeal teratomas (two), malignant sacrococcygeal teratoma (one), and perineal rhabdomyosarcoma (one). Protective colostomy was used in four patients. The parameters that we analysed included technical details, possible complications, perineal cosmetic appearance, and outcome. No complications were experienced. The postoperative cosmetic perineal appearance was excellent in all patients, and continence, when assessed, was always considered satisfactory. All tumours underwent complete gross resection. However, one patient with malignant sacrococcygeal teratoma died as a result of the malignant process 2 years after surgery. Although our study was carried out on a small series of patients, it confirmed that perineal sagittal approaches can be used not only for ARM but also for other conditions involving perirectal pouches, presacral space, and urogenital structures, as these approaches are safe and provide excellent cosmetic results as well as satisfactory functional outcome. Although tumours can be treated via these approaches, outcome remains related to the nature and malignancy of the disease itself.

Currarino syndrome: proposal of a diagnostic and therapeutic protocol.

BACKGROUND/PURPOSE: The Currarino syndrome (CS) is a peculiar form of caudal regression syndrome (CRS) characterized by the association of hemisacrum, anorectal malformation (ARM), and presacral mass. The authors analyzed retrospectively their series, and they propose a multidisciplinary diagnostic and therapuetic protocol that until now has not been introduced. METHODS: A series of 6 patients with CS is presented. Five of them were treated initially in other centers. None of them had an early diagnosis. All presented associated anomalies; in 50%, Hirschsprung's disease (HD) and other dysganglionoses were present. One patient died of a presacral ectopic nephroblastoma. RESULTS: Depending on the expressivity, 3 types of CS can be identified, complete, mild, and minimal. Dysganglionoses and HD can be considered part of CS. A multidisciplinary diagnostic and therapeutic protocol is presented. Main points are sacrum x-Ray, molecular genetic diagnosis, radiologic evaluation of every member of CS families, magnetic resonance (MR) evaluation of patient spine and pelvis, suction rectal biopsies, and search for associated anomalies. CONCLUSIONS: This protocol could give a valid contribution to the treatment of CS, allowing an early diagnosis and proposing a rational timing of multidisciplinary surgical procedures. Early diagnosis and treatment are essential to avoid morbidity and mortality from an undiagnosed presacral mass.

Diagnostic and therapeutic approach to multiple endocrine neoplasia type 2B in pediatric patients.

Multiple endocrine neoplasia (MEN) 2B is a hereditary syndrome including medullary thyroid carcinoma (MTC), pheochromocytoma, gastrointestinal (GI) disorders, marfanoid facies, and multiple ganglioneuromas. MTC is the major cause of mortality, and often appears during the 1st decade of life. RET proto-oncogene mutations are responsible for MEN 2B. Other RET mutations cause MEN 2A syndrome, familial MTC, or Hirschsprung's disease. We studied three MEN 2B patients with the aim of delineating the best diagnostic and therapeutic protocol. The gold standards for diagnosis are histochemical study of the rectal mucosa and molecular analysis of RET, which in familial cases detects MEN 2B at a preclinical stage so that early total prophylactic thyroidectomy can be performed. In non-familial cases, the diagnosis can be suggested by the presence of GI symptoms, ganglioneuromas, and/or the typical facies. The intestinal innervation pattern, analyzed with the acetylcholinesterase technique, is pathognomonic for MEN 2B. In our protocol a rectal biopsy is, therefore, the first measure. The surgical treatment of MEN 2B is total thyroidectomy with cervical lymphadenectomy of the central compartment of the neck. When possible, this intervention should be performed prophylactically before 1 year of age.

Associated anomalies in intestinal neuronal dysplasia.

BACKGROUND/PURPOSE: Intestinal neuronal dysplasia (IND) is a complex alteration of the enteric nervous system (ENS) that may involve rectum, colon, or the whole intestine. This disorder is a frequent cause of intestinal dysmotility and pseudo-obstruction in the first 3 years of life. The aim of this study was to identify possible associations and correlations of IND with other gastrointestinal and nongastrointestinal anomalies. METHODS: From 1986 to 2000, 95 cases of IND type B without aganglionosis were diagnosed. Fifteen cases were diffuse IND, whereas the remaining 80 were rectocolonic neuronal dysplasia. The diagnosis was performed on rectal suction biopsy specimens taken 2 to 10 cm above the pectinate line. Acetylcholinesterase (AChE), lactic dehydrogenase (LDH), and NADPH-diaphorase (NADPH-d) histochemical techniques were performed on serial cryostatic sections. We used Schärli and Meier-Ruge criteria (1981) for the diagnosis of IND until 1992, when we adopted Borchard et al criteria (1991). A retrospective analysis of the clinical data was performed to identify IND-associated anomalies. RESULTS: These anomalies included anorectal malformations (9 cases), intestinal malrotation (8), megacystis (5), congenital short small bowel (4), hypertrophic pyloric stenosis (3), necrotizing enterocolitis (2), mental retardation (2), short stature (2), facial dysmorphism (2), Down syndrome (1), intestinal atresia (1), diffuse intestinal angiomatosis (1), histiocytosis (1), microvillus agenesia (1), and hearing loss (1). Overall, 43 associated anomalies were found in 29 IND cases (30.5%). Gastrointestinal anomalies accounted for 67.4% (29 of 43 anomalies) of associated disorders. The incidence of associated anomalies was higher in diffuse IND (80% of cases, 12 of 15) than in rectocolonic forms (21.2%, 17 of 80). CONCLUSIONS: Unlike Hirschsprung's disease, which is determined genetically, IND pathogenesis is unknown. The analysis of associated anomalies in IND population is an important clinical approach to investigate possible pathogenetic correlations. Two recessive syndromes were identified (3 families). The first was characterized by IND, intestinal malrotation, and congenital short bowel, the second by IND, short stature, mental retardation, and facial dysmorphism. In this study, gastrointestinal anomalies accounted for 67.4% of all associated disorders. These data suggest a strong correlation between IND and intestinal development. Abnormalities of the fetal ENS could determine the IND phenotype, which is likely to contribute to the pathogenesis of different intestinal malformations and in particular of anorectal and "rotation" anomalies.

Histologic study of peritoneal adhesions in children and in a rat model.

Peritoneal adhesions (PA) represent a major cause of morbidity in pediatric surgical patients. The pathogenesis is still largely unknown. A possible role could be played by foreign bodies (FB) accidentally contaminating the operative field during surgery. We report a histologic study of PA in a rat model and in children, investigating the role of FB in their formation. Abdominal adhesions were studied in 18 rats. In 6 (group A) we performed a laparotomy and rubbed the visceral and parietal peritoneum with a cotton bud. In 6 (group B) we performed a minimal laparotomy and injected powdered autologous and heterologous material into the peritoneal cavity, avoiding any peritoneal abrasions. In 6 (group C) we performed a laparotomy and applied both treatment methods, i.e., rubbing and injection of FB. After 1 month, at autopsy rats were classified according to the presence and grade of surgical adhesions. Twenty-two PA were also collected from seven children undergoing abdominal surgery in whom one or more procedures had been previously performed. The adhesions were stained with hematoxylin-eosin and Giemsa stains for histologic examination. Adhesions were found in 4 rats of group A and all 6 rats of group C. None were identified in group B. Group C rats showed a higher grade of adhesions with respect to group A. In both humans and animals PA were always found to coexist with microscopic particles of solid substances, which were incorporated inside the connective tissue. However, after simple injection of FB into the abdominal cavity we did not observe any PA. These data suggest that two different stimuli are necessary for adhesion formation: a direct lesion of the mesothelial layers and a solid substrate (FB). We underline the importance of reducing contamination with FB during surgery. On the basis of these considerations, the laparoscopic approach seems to be particularly pertinent.

Mouse-isolated plexus differentiates neural crest precursors into enteric neuroblasts.

Aim of this study was to investigate, for the first time, whether isolated newborn mouse enteric plexus could induce in vitro differentiation of the vagal neural crest-derived cells into enteric neuroblasts. Fragments of the myenteric plexus were isolated from the small intestine of 6-day-old Swiss mice and were collected and stored in DMEM-F12 medium, then cultured on polymerized human fibronectin layer. The vagal portion of the neural tube, isolated from a 9.5-day-old Swiss mouse embryo, was put in the same chamber slides where the isolated myenteric plexus had been cultured for 3 days. The vagal neural crest-derived cells migrated onto the polymerized human fibronectin layer and formed a crown of cells around the neural tube. After 6 days, the cultures were stopped and studied immunohistochemically for anti-NF160 KD, anti-TH, and RetR5 antibodies to analyse the differentiation stage of the cultured cells. Analysis of results included the comparison of two culture groups: Group 1, used as control, in which vagal neural crest-derived cells were put in DMEM-F12, supplemented only with 10 % of FCS; Group 2, in which vagal neural crest-derived cells were put in the same medium as Group 1, with the addition of myenteric plexus fragments isolated from newborn mice to form the co-culture. The following results were obtained: in Group 1 the neural tubes originated a cell population strongly positive for anti-NF160 and anti-TH Ab, but negative for RetR5 Ab. This positivity was found both in the cells adjacent to the neural tube and in those migrating from it distally. The Group 2 originated cells, which after migration were positive for anti-NF160 and for anti-TH antibodies. In addition, in this culture group, the cells which migrated from the neural tube were positive for anti-RetR5 antibody. The co-culture used in this study induces the differentiation of vagal stem cells into enteric neuroblasts, cells TH+ and RetR5+. These cells, after reaching the embryonic intestine, migrate to colonize the hindgut and form the ENS. Therefore this biotechnology seems a good method to obtain in vitro enteric precursors of ENS.

Sacral development in anorectal malformations and in normal population.

BACKGROUND: The sacral ratio (SR) was proposed by Alberto Peña in 1995 as a reliable tool to evaluate sacral development in anorectal malformations (ARM). The SR is obtained by comparing sacrum size with fixed bony parameters of the pelvis. In previous studies, the average normal SR was calculated to be 0.74 for the anteroposterior view (APSR) and 0.77 for the lateral view (LSR). OBJECTIVES: (a) To evaluate the range of variability of the SR in a normal population with age as a possible variable factor. (b) To evaluate the reliability of the SR as a prognostic factor in patients with ARM. MATERIALS AND METHODS: We studied pelvic radiographs of 147 normal children in order to calculate a normal range of values for the SR. In 59 children with ARM, clinical parameters of faecal and urinary continence, spinal cord anomalies (as detected by MRI) and rectal innervation patterns (studied by enzymo-histochemistry) were correlated with SR values by Snedecor's 'F' test and Bravais-Pearson's 'r' correlation index. In 25 cases (15 children with ARM and 10 controls), multiple measurements of SR were obtained at different ages. RESULTS: Normal values for APSR ranged from 0.52 to 1.12, with an average of 0.74. Normal values for LSR ranged from 0.52 to 1.18, with an average of 0.75. Low SR values (below 0.52) correlated well with spinal cord anomalies and with unfavourable functional prognosis in children with ARM. APSR and LSR values increased with age in the normal population, while they decreased in patients with ARM. CONCLUSIONS: The SR has a wide range of normal values, and should be considered truly pathological when lower than 0.52, in either the AP or lateral views. Age has a significant influence on SR values.

A new rapid acetylcholinesterase histochemical method for the intraoperative diagnosis of Hirschsprung's disease and intestinal neuronal dysplasia.

The most commonly used acetylcholinesterase (AChE) method for the diagnosis of Hirschsprung's disease (HD) and intestinal neuronal dysplasia (IND) was first introduced in 1964 by Morris Karnovsky and Logan Roots. This technique requires about 80 - 120 minutes incubation time and cannot be used for the intraoperative diagnosis of HD and IND. To avoid these limitations, in 1994 Kobayashi et al first proposed an accelerated modified method in two different versions, the first using diaminobenzydine (DAB) reagent, the second using 4-chloro-1-naphthol as final reagent. In the present study, we propose a new rapid variation of AChE staining which avoids the use of DAB and naphthol, notably toxic reagents, but follows the same acceleration principle of Kobayashi's technique. Our modified rapid AChE requires a total incubation time of only 8 minutes, which is compatible with intraoperative histochemical examination purposes. Intraoperative seromuscular or full-thickness intestinal biopsies were obtained from 92 children affected by intestinal dysganglionoses. The biopsies were frozen and cut in 15 microm cryostatic sections. Rapid AChE was performed with a special incubation medium using 3-amino-9 ethylcarbazole (AEC) as chromogenic substance. The two complementary histochemical techniques alpha-naphthylesterase (ANE) and lactate-dehydrogenase (LDH) were also used intraoperatively for the staining of ganglion cells. The diagnosis was confirmed postoperatively with conventional AChE Karnovsky technique, comparing the extensions of hyperganglionic, hypoganglionic and aganglionic segments in each studied case. The new rapid AChE modified method can identify ganglion cells and fibers using a dark brown precipitate. In all the cases studied, the intestinal innervation pattern identified with this modified technique was similar to that obtained with Karnovsky AchE. Seventy-eight HD, 8 isolated IND and 6 HD associated with an evident IND segment were diagnosed. This new rapid AChE histochemical technique avoids the use of DAB and naphthol, and can thus be considered safe for operators. Rapid AChE is a valid tool for both the evaluation of aganglionosis extension and for the identification of IND pattern during surgery. We recommend this very reliable method for the intraoperative diagnosis of HD and IND, in association with other enzymatic markers of ganglion cells (ANE or LDH). We propose the following diagnostic protocols: a) for preoperative histochemical study: conventional AChE plus LDH and NADPH-diaphorase; b) for intraoperative study: rapid AChE plus ANE.

Solo-RBT: a new instrument for rectal suction biopsies in the diagnosis of Hirschsprung's disease.

BACKGROUND/PURPOSE: Preoperative histochemistry on rectal mucosal-submucosal specimens is the most important step in the diagnosis of Hirschsprung's disease and other dysganglionoses. Today, rectal mucosal-submucosal biopsy specimens are obtained by suction with the widely used tool first designed by Noblett in the late 1960s. The authors developed a new instrument, for which a patent has already been filed, for one-hand execution of rectal suction biopsies, which will make this operation easier and faster. METHODS: The authors modified the old tool but maintained the cutting method described by Noblett. The authors' innovative automatic tool (Solo-RBT) is based on the possibility of sequencing suction and cutting of the rectal mucosa just by pressing a "trigger." The trigger activates a plunger to obtain the vacuum necessary for the suction and a cutter for mucosal sampling. To perform a correct biopsy in children with different weight and in adults, Solo-RBT can be adjusted suitably to obtain automatically the vacuum required in each case. Additionally, this tool is provided with 2 different sizes of both capsules and cutters, and it can be disassembled completely for easy cleaning, maintenance, and sterilization. RESULTS: The instrument was tested clinically on 62 children (189 biopsies), and it proved to be versatile, atraumatic, and extremely handy, because it can be used by just 1 physician who only needs to press the trigger to obtain the biopsy. CONCLUSIONS: Solo-RBT not only maintains the benefits (atraumatic, easy to use, rapid) and the main characteristic (cutting system) of Noblett's tool but it also improves its features and eliminates most of its disadvantages. Therefore, Solo-RBT represents a significant improvement in the diagnosis of Hirschsprung's disease and other dysganglionoses.

Pathogenesis of Hirschsprung's disease.

Hirschsprung's disease is an inherited disorder showing incomplete penetrance and variable expressivity. Genetic mapping and mutation screening of candidate genes, together with the study of several natural and knockout animal models, clearly have shown the involvement of several different genes in the pathogenesis of Hirschsprung's disease. Among these genes, the RET proto-oncogene accounts for the highest proportion of both familial and sporadic cases, with a wide range of mutations scattered along its entire coding region. The low detection rate of RET mutations in Hirschsprung patients also led to different hypotheses, such as the existence of additional Hirschsprung genes. Different animal and human genetic studies have identified 6 Hirschsprung genes: RET proto-oncogene (RET), endothelin 3 (EDN3), endothelin B receptor gene (EDNRB), glial-cell-line-derived neurotrophic factor (GDNF), endothelin converting enzyme (ECE1), gene encoding the Sry-related transcription factor SOX10 (SOX10). Microenvironmental factors also can play a role in the pathogenesis of aganglionosis. The developmental process of the crest-derived progenitor cells is sensitive to the level of different molecules. The expression deficit of different factors (GDNF, NTN) in the hindgut, in the absence of genetic mutations, could determine a missed activation of the receptor system, causing enteric neuroblast migration arrest.