Acetylcholinesterase activity in suction biopsies of the rectum in the diagnosis of Hirschsprung's disease

The Pathologist's Role in the Diagnosis of Hirschsprung's Disease

INTRODUCTION

 The possibilities, recent advances, and pitfalls in the histopathologic workup of specimens submitted for the diagnosis of Hirschsprung's disease (HSCR) are presented.

MATERIALS AND METHODS

 A literature research was performed in the database PubMed including the years 2000 to 2024.

RESULTS

 The pathologist is involved in the diagnosis of HSCR in three scenarios: (1) the primary diagnosis in a child with the typical clinical symptoms, (2) the intra-operative guidance of surgery in a case where the diagnosis is already established, and (3) the confirmation of the diagnosis and the documentation of the extent of the disease in the resected specimen. Identification of ganglion cells in the enteric neural plexuses excludes HSCR, and the histological confirmation of a complete absence of these ganglion cells is the gold standard for its diagnosis. However, difficulties in the detection of ganglion cells with standard stains and/or a limited amount of tissue in the specimen submitted for diagnosis make supportive histologic stains and techniques, e.g., calretinin immunohistochemistry or acetylcholinesterase histochemistry necessary for an unequivocal diagnosis of HSCR.

CONCLUSIONS

 Improving the diagnostic accuracy of this life-threating disease is an interdisciplinary task. A good communication between pathologist and clinician, as well as mutual knowledge of skills and challenges of the other discipline, is necessary for a successful diagnostic teamwork.

The Diagnostic Value of Immunohistochemistry Markers in Hirschsprung Disease; A Systematic Review and Meta-analysis

BACKGROUND

Immunohistochemistry (IHC) markers are employed to improve the diagnostic yield when testing for Hirschsprung disease (HSCR). Yet, a superior test has not been identified.

OBJECTIVES

We aimed to determine the diagnostic test accuracy (DTA) of IHC markers.

METHODS

We conducted database search for studies reporting IHC staining on rectal biopsy investigating for HSCR. We constructed 2 × 2 contingency tables, and calculated DTA estimates in pooled and paired testing using random-effect model meta-analysis.

RESULTS

Twenty eight IHC markers from 107 studies were used to investigate for HSCR in 10891 children. In pooled analysis; calretinin sensitivity and specificity were superior to acetylcholinesterase, S100, and peripherin [98 % (CI; 0.95-0.99) & 99 % (CI; 0.97-0.99)], [94 % (CI; 0.86-0.97) & 99 % (CI; 0.96-0.99)], [92 % (CI; 0.85-0.96) & 97 % (CI; 0.89-0.99)] and [91.7 % (CI; 0.54-0.98) & 94.8 % (CI; 0.59-0.99)], respectively. In paired analysis calretinin diagnostic odds ratio was superior to hematoxylin and eosin (H&E), acetylcholinesterase and S100: [3349 (PI; 551.3-22667.2) vs 345.3 (PI; 54.9-2394.2)], [300.9 (PI; 13.3-4146.9) vs 34.6 (PI; 2.2-363.9)] and [696.9 (PI; 91.2-3401.7) vs 196.9 (PI; 29.8-890.5)], respectively. In biopsies labelled inadequate for H&E testing, calretinin specificity to rule out HSCR reached 92 % (CI; 0.288-0.998).

CONCLUSIONS

IHC provides additional diagnostic value over H&E. Calretinin appears to be, currently, a superior IHC marker. The available literature is of variable quality, cautious interpretation of the findings should be considered.

LEVEL OF EVIDENCE

III.

A new systematization of histological analysis for the diagnosis of Hirschsprung's disease

BACKGROUND

Hirschsprung's Disease (HD) is characterized by intestinal sub-occlusion and the absence of enteric ganglion cells. A rectal biopsy examination is performed to confirm the diagnosis. In a recent study, we demonstrated that the analysis of 60 sections of rectal mucosa and submucosa stained by H&E may ensure a 90% diagnostic accuracy. Although the need to analyze so many sections makes the process of reading the slides more time-consuming, this encouraged us to study their distribution in the healthy rectal submucosa, to simplify the diagnosis.

OBJECTIVES

To develop a method that facilitates HD diagnosis by studying the distribution of ganglion cells in the submucosal plexus.

METHODS

Using the calretinin technique, we studied the distribution of plexuses in 60 fragments of rectal submucosa from 19 cadavers. After the study, the reading method created was used for diagnosis in 47 cases of suspected HD, using H&E staining. The accuracy was verified by comparing the results obtained with H&E to those obtained with the acetylcholinesterase technique, the golden standard in our laboratory.

RESULTS

The study of submucosal plexus distribution showed that just by examining the submucosal region every 20 µm, approximately, it is possible to locate a ganglionic plexus, and we have already been able to diagnose HD with 93% accuracy.

CONCLUSION

The study of ganglion cell distribution enabled the creation of a simplified method for reading the slides. The method applied achieved good accuracy and it can be used as an alternative method in HD diagnosis.

Hirschsprung Disease for the Practicing Surgical Pathologist

OBJECTIVES

Hirschsprung disease (HD) is a congenital condition defined by the absence of ganglion cells in the distal-most portion of the gastrointestinal tract. Biopsies and resections for HD can be adrenaline inducing for the general surgical pathologist because specimens are infrequent; HD is 1 of only a few neuroanatomic diseases that general surgical pathologists diagnose; numerous preanalytic factors (eg, biopsy adequacy, surgeon sampling protocol, processing artifacts) can affect histologic interpretation; and most importantly, the diagnosis has high stakes.

METHODS

We provide a comprehensive overview of the background, relevant clinical procedures, and pathologic assessment of HD. Grossing and frozen section protocols, an algorithmic approach to diagnosis, and histologic pearls and pitfalls are also discussed.

RESULTS

Evaluation and recognition of the features of HD have evolved significantly in the past 2 decades with the discovery of the value of calretinin immunohistochemistry in the late 2000s and the recent development of straightforward and reproducible histologic criteria for identification of the HD transition zone.

CONCLUSIONS

These advancements have substantially improved the pathologist's ability to reliably evaluate for HD. Nonetheless, as with any high-stakes surgical pathology specimen, clear communication with the clinical team is essential.

Myelin Protein Zero Immunohistochemistry Is Not a Reliable Marker of Extrinsic Mucosal Innervation in Patients With Hirschsprung Disease

BACKGROUND

Innervation of aganglionic rectum in Hirschsprung disease derives from extrinsic nerves which project from cell bodies located outside the bowel wall and markers that distinguish extrinsic from intrinsic innervation are diagnostically useful. Myelin protein zero (MPZ) is a putative marker of extrinsic glial cells which could distinguish mucosal innervation in aganglionic vs ganglionic colon.

METHODS

Sections and protein blots from ganglionic and aganglionic colon were immunolabeled with MPZ-specific antibodies.

RESULTS

Immunolabeling of MPZ with a chicken polyclonal or mouse monoclonal antibody confirmed glial specificity and reliably labeled hypertrophic submucosal nerves in Hirschsprung disease. In contrast, a rabbit polyclonal antibody strongly labeled extrinsic and intrinsic nerves, including most mucosal branches. Immunoblots showed MPZ is expressed in mucosal glial cells, albeit at lower levels than in extrinsic nerves, and that the rabbit antibody is more sensitive that the other two probes. Unfortunately, none of these antibodies consistently distinguished mucosal innervation in aganglionic vs ganglionic rectum.

CONCLUSIONS

The results suggest that (a) glial cell myelin protein zero expression is influenced more by location (mucosa vs submucosa) than the extrinsic vs intrinsic origin of the accompanied nerves and (b) myelin protein zero immunohistochemistry has limited value as a diagnostic adjunct for Hirschsprung disease.

Cholinergic Signaling Attenuates Pro-Inflammatory Interleukin-8 Response in Colonic Epithelial Cells

Infants affected by Hirschsprung disease (HSCR), a neurodevelopmental congenital disorder, lack ganglia of the intrinsic enteric nervous system (aganglionosis) in a variable length of the colon, and are prone to developing severe Hirschsprung-associated enterocolitis (HAEC). HSCR patients typically show abnormal dense innervation of extrinsic cholinergic nerve fibers throughout the aganglionic rectosigmoid. Cholinergic signaling has been reported to reduce inflammatory response. Consequently, a sparse extrinsic cholinergic innervation in the mucosa of the rectosigmoid correlates with increased inflammatory immune cell frequencies and higher incidence of HAEC in HSCR patients. However, whether cholinergic signals influence the pro-inflammatory immune response of intestinal epithelial cells (IEC) is unknown. Here, we analyzed colonic IEC isolated from 43 HSCR patients with either a low or high mucosal cholinergic innervation density (fiber-low versus fiber-high) as well as from control tissue. Compared to fiber-high samples, IEC purified from fiber-low rectosigmoid expressed significantly higher levels of IL-8 but not TNF-α, IL-10, TGF-β1, Muc-2 or tight junction proteins. IEC from fiber-low rectosigmoid showed higher IL-8 protein concentrations in cell lysates as well as prominent IL-8 immunoreactivity compared to IEC from fiber-high tissue. Using the human colonic IEC cell line SW480 we demonstrated that cholinergic signals suppress lipopolysaccharide-induced IL-8 secretion via the alpha 7 nicotinic acetylcholine receptor (a7nAChR). In conclusion, we showed for the first time that the presence of a dense mucosal cholinergic innervation is associated with decreased secretion of IEC-derived pro-inflammatory IL-8 in the rectosigmoid of HSCR patients likely dependent on a7nAChR activation. Owing to the association between IL-8 and enterocolitis-prone, fiber-low HSCR patients, targeted therapies against IL-8 might be a promising immunotherapy candidate for HAEC treatment.

Reevaluation of concurrent acetylcholinesterase and hematoxylin and eosin staining for Hirschsprung's disease

BACKGROUND

Acetylcholinesterase (AChE) histochemistry has been widely performed for the histopathological diagnosis of Hirschsprung's disease (HD). However, we occasionally come across diagnostic difficulties. We conducted concurrent AChE histochemistry and hematoxylin and eosin (HE) staining to validate the ancillary value of this technique.

METHODS

Of 177 patients diagnosed using AChE histochemistry from January 2014 to December 2016, 90 patients underwent formalin-fixed paraffin-embedded HE staining. The histopathological findings and diagnostic abilities were investigated and compared retrospectively.

RESULTS

The sensitivity, specificity, accuracy, and kappa index of AChE histochemistry and HE staining were 94.1%, 100%, 98.9%, and 0.964 and 76.5%, 84.9%, 83.3%, and 0.530, respectively. The specificity, accuracy and kappa index of AChE histochemistry were significantly higher than those of HE staining (P < 0.001, <0.001, and <0.05). Hematoxylin and eosin staining supported the suspected diagnosis of total colon aganglionosis at the initial biopsy; furthermore, HE staining helped confirm the distinct shape of ganglion cells and hypertrophic nerve bundles.

CONCLUSION

We re-confirmed that AChE histochemistry is an excellent method for diagnosing HD. Although the diagnostic ability of HE staining is limited, it has acceptable utility as an ancillary method. Thus, AChE staining is a useful test and it should be performed together with HE staining.

Label-free detection of human enteric nerve system using Raman spectroscopy: A pilot study for diagnosis of Hirschsprung disease

BACKGROUND

Hirschsprung disease (HSCR) is characterized by the absence of an enteric nerve system (ENS). To remove aganglionosis, bowel reconstruction is only a curative treatment. It is mandatory to identify the extent of aganglionosis during surgery. Raman spectroscopy is a nondestructive chemical analysis technique that provides detailed information regarding molecular vibrations. The purpose of this study is to detect the ENS using Raman spectroscopy in the human intestine for diagnosis of HSCR.

METHODS

The Raman spectra of each layer of the gastrointestinal wall were collected from surgical specimens of the human rectum. Based on collected spectral data, principal component analysis was performed to determine the ENS. Subsequently, the Raman spectra of HSCR sections were analyzed.

RESULTS

Molecular structures of the gastrointestinal wall were characterized by Raman spectroscopy. Raman spectroscopy could discriminate between ganglion and muscle layers, and the spectra of the border between muscle layers in the aganglionosis were collagen-associated peaks. Either absence on presence of ENS was also confirmed in HSCR material.

CONCLUSIONS

Label-free detection of the ENS was successfully demonstrated using Raman spectroscopy. Since this is a preliminary study, the strategy which may contribute to differentiate between ganglionic and aganglionic segments using noninvasive techniques in HSCR should be evaluated by prospective studies in near future.

Lack of Mucosal Cholinergic Innervation Is Associated With Increased Risk of Enterocolitis in Hirschsprung's Disease

BACKGROUND & AIMS

Hirschsprung's disease (HSCR) is a congenital intestinal motility disorder defined by the absence of enteric neuronal cells (ganglia) in the distal gut. The development of HSCR-associated enterocolitis remains a life-threatening complication. Absence of enteric ganglia implicates innervation of acetylcholine-secreting (cholinergic) nerve fibers. Cholinergic signals have been reported to control excessive inflammation, but the impact on HSCR-associated enterocolitis is unknown.

METHODS

We enrolled 44 HSCR patients in a prospective multicenter study and grouped them according to their degree of colonic mucosal acetylcholinesterase-positive innervation into low-fiber and high-fiber patient groups. The fiber phenotype was correlated with the tissue cytokine profile as well as immune cell frequencies using Luminex analysis and fluorescence-activated cell sorting analysis of colonic tissue and immune cells. Using confocal immunofluorescence microscopy, macrophages were identified in close proximity to nerve fibers and characterized by RNA-seq analysis. Microbial dysbiosis was analyzed in colonic tissue using 16S-rDNA gene sequencing. Finally, the fiber phenotype was correlated with postoperative enterocolitis manifestation.

RESULTS

The presence of mucosal nerve fiber innervation correlated with reduced T-helper 17 cytokines and cell frequencies. In high-fiber tissue, macrophages co-localized with nerve fibers and expressed significantly less interleukin 23 than macrophages from low-fiber tissue. HSCR patients lacking mucosal nerve fibers showed microbial dysbiosis and had a higher incidence of postoperative enterocolitis.

CONCLUSIONS

The mucosal fiber phenotype might serve as a prognostic marker for enterocolitis development in HSCR patients and may offer an approach to personalized patient care and new therapeutic options.

Cholinergic innervation and ganglion cell distribution in Hirschsprung's disease

BACKGROUND

The diagnostic gold standard of Hirschsprung's disease (HD) is based on the histopathological assessment of colorectal biopsies. Although data on cholinergic innervation and ganglion cell (GC) distribution exist, only few studies have examined these two key features together. We assessed the pattern of cholinergic innervation and the amount of GCs in colorectal specimens of 14 HD patients.

METHODS

We established a semi-quantitative score for cholinergic innervation using acetylcholinesterase (AChE) enzyme histochemistry and quantitatively analyzed the number of GCs via NADH tetrazolium reductase (NADH) enzyme histochemistry. We examined both the entire length of the resected specimens as well as defined areas of the transition zone of both pathological and healthy appearing segment.

RESULTS

High AChE score values were associated with absence of GCs, and AChE scores were inversely correlated with the number of GCs. Nevertheless, we observed several cases in which one of the two features revealed a normal distribution pattern, whereas the other still displayed pathological features.

CONCLUSIONS

Our data support the need for transmural colon biopsies, to enable the best evaluation of both cholinergic innervation and GCs for a reliable assessment of HD.

Acetylcholinesterase staining for the pathological diagnosis of Hirschsprung's disease

Hirschsprung's disease (HD) is a congenital disease manifesting various degrees of functional bowel obstruction caused by the absence of enteric ganglion cells, which are usually absent in the colonic segment of the HD patient. Because the aganglionic segment of HD always includes the rectum, pathological diagnosis can be made using a rectal sample. HD should be diagnosed as early as possible because serious complications, such as acute enterocolitis or toxic megacolon, can develop without a definitive diagnosis and appropriate treatment. In the mid-1900s, HD was diagnosed by HE staining of specimens obtained by full-thickness biopsy. Since then, the combination of rectal mucosal biopsy and rubeanic acid-amplificated AChE staining has been brought about by the following milestones: the discovery that the submucosal plexus and the intermuscular plexus had the same level of nerve migration; the findings of research on acetylcholine (ACh) and acetylcholinesterase (AChE) in the intestinal tract; and the establishment of a rubeanic acid amplification method. Consequently, the diagnostic rate of HD improved dramatically in the 1980s. This review outlines the history of diagnostic methods for HD, the roles of ACh and AChE in the intestine, and the method of AChE staining.

Accuracy of colonic mucosal patterns at contrast enema for diagnosis of Hirschsprung disease

BACKGROUND

Various patterns of colonic mucosal irregularity have been recorded on contrast enema, each with individually very low sensitivity, but high specificity.

OBJECTIVE

To assess the accuracy of the radiologic features of Hirschsprung disease utilising a unifying stratification of any form of colonic mucosal irregularity on contrast enema.

MATERIALS AND METHODS

We conducted a retrospective study of children with suspected Hirschsprung disease managed at a tertiary South African hospital from January 2009 through April 2015. Three observers independently reviewed abdominal radiographs and contrast enemas. The enema analysis included a unifying category of any form of colonic mucosal irregularity. Radiologic features were compared with rectal biopsy results. We used descriptive statistics and the Fisher exact test to compare the radiologic features of children with and without Hirschsprung disease.

RESULTS

Ninety-two children with median age of 37 days (range 3 days to 11 years) were included; 50 had biopsy-proven Hirschsprung disease. On enema, any mucosal irregularity, a transition zone and recto-sigmoid ratio inversion were associated with Hirschsprung disease (all P<0.01). Mucosal irregularity showed 96% sensitivity (95% confidence interval [CI] 86.3-99.5) and 71.4% specificity (CI 55.4-84.3); a transition zone showed 86% sensitivity (CI 73.3-94.2) and 90.5% specificity (CI 77.4-97.3); and recto-sigmoid ratio inversion showed 78% sensitivity (CI 64.0-88.5) and 83.3% specificity (CI 68.3-93.0).

CONCLUSION

Colonic mucosal irregularity on contrast enema has high sensitivity and moderate specificity for Hirschsprung disease.

Visualization of the human enteric nervous system by confocal laser endomicroscopy in Hirschsprung's disease: An alternative to intraoperative histopathological diagnosis?

BACKGROUND

Hirschsprung's disease is a congenital abnormality of the enteric nervous system (ENS) presenting severe constipation soon after birth due to the lack of ganglion cells in the distal gut. Surgery for Hirschsprung's disease requires an intraoperative histopathological diagnosis to assess the extent of aganglionosis. Confocal laser endomicroscopy (CLE) is a novel endoscopic technique allowing real-time, in vivo analysis of cellular details during ongoing endoscopy. In this study, we evaluated the possibility of a new application of CLE to provide real-time observations of the ENS in patients with Hirschsprung's disease. In this preclinical feasibility study, we assessed the visualization of the ENS by CLE using surgically resected intestines.

METHODS

The subjects were nine patients who underwent pull-through surgery for Hirschsprung's disease between September 2014 and March 2016. The colon specimens were stained with 0.1% cresyl violet and evaluated using CLE. We compared the CLE findings with those of the histopathological examination.

KEY RESULTS

The ENS was clearly visualized as a ladder-like structure in the ganglionic segment but was not observed in the aganglionic segment. Of the 69 samples, corresponding positive and negative results for both CLE and the histopathology were obtained in 61 (88%). In addition, CLE was able to visualize unique, wavy structures comprising thick nerve bundles characteristic of the aganglionic/transition zone in Hirschsprung's disease.

CONCLUSIONS AND INFERENCES

As a novel tool for visualizing the human ENS, CLE has the potential to revolutionize how pediatric surgeons identify the level of ganglionosis during surgery for Hirschsprung's disease and may be a superior alternative to intraoperative histopathological diagnosis.

Are We Underdiagnosing Hirschsprung Disease?

Hirschsprung disease (HSCR) is conventionally defined as aganglionosis of the distal rectum and a variable length of proximal contiguous bowel with a transition zone of ganglionic, but neuroanatomically abnormal, bowel located immediately upstream. Recent improvement in our understanding of the pathology and genetics of HSCR and relevant animal models indicates highly variable expressivity. The spectrum of intestinal neuropathology includes patients with very short-segment aganglionosis, limited to the distal 1 to 2 cm of the rectum, and possibly patients with no true aganglionic segment, but nonphysiological transition zone pathology in their distal rectums. The presence or absence of submucosal ganglion cells in a rectal biopsy is not sufficient to exclude these patients, in whom submucosal nerve hypertrophy and/or abnormal cholinergic mucosal innervation may be the only diagnostic clues. In addition, diagnosis or exclusion of HSCR by rectal biopsy now relies in part on mucosal patterns of calretinin immunohistochemistry, with less emphasis on submucosal tissue adequacy and assessment of cholinergic innervation. These recent trends in the surgical pathology approach to rectal biopsies may miss patients at the phenotypically milder end of the malformation spectrum, with profound implications for subsequent management, prognosis, and genetic counseling.

Remodeling of Rectal Innervation After Pullthrough Surgery for Hirschsprung Disease: Relevance to Criteria for the Determination of Retained Transition Zone

BACKGROUND

After pullthrough surgery for Hirschsprung disease (HSCR), Glut1-positive submucosal nerve hypertrophy is used to diagnose retained transition zone in the neorectum. We hypothesized that pelvic nerves, severed during pullthrough surgery, sprout into the neorectum to mimic transition zone.

METHODS

The density (nerves/100x field) and maximum diameter of Glut1-positive submucosal nerves were measured in biopsies and redo resections from 20 patients with post-pullthrough obstructive symptoms. Their original and/or redo resections excluded unequivocal features of transition zone (myenteric hypoganglionosis or partial circumferential aganglionosis) in 17. Postoperative values were compared with control data from 28 cadaveric and 6 surgical non-HSCR specimens, and 14 primary HSCR resections. When possible, nerves were tracked from attached native pelvic soft tissue or aganglionic rectal cuff into the pulled-through colon.

RESULTS

Glut1-positive submucosal nerves were not present in the 11 colons of non-HSCR infants less than 1 year of age, except sparsely in the rectum. In 17 older non-HSCR controls, occasional Glut1-positive nerves were observed in prerectal colon and were larger and more numerous in the rectum. In redo resections, Glut1-positive submucosal innervation in post-pullthrough specimens did not differ significantly from age-appropriate non-HSCR rectal controls and pelvic Glut1-positive nerves were never observed to penetrate the pulled-through colon. However, the density and caliber of Glut1-positive nerves in the neorectums were significantly greater than expected based on the prerectal location from which the pulled-through bowel originated.

CONCLUSIONS

Submucosal innervation in post-pullthrough specimens does not support the hypothesis that native pelvic nerves innervate the neorectum, but suggests remodeling occurs to establish the age-appropriate density and caliber of rectal Glut1-positive innervation. The latter should not be interpreted as transition zone pullthrough in a rectal biopsy from a previously done pullthrough.

Digital pathology imaging and computer-aided diagnostics as a novel tool for standardization of evaluation of aganglionic megacolon (Hirschsprung disease) histopathology

Based on a recently introduced immunohistochemical panel (Bachmann et al. 2015) for aganglionic megacolon (AM), also known as Hirschsprung disease, histopathological diagnosis, we evaluated whether the use of digital pathology and 'machine learning' could help to obtain a reliable diagnosis. Slides were obtained from 31 specimens of 27 patients immunohistochemically stained for MAP2, calretinin, S100β and GLUT1. Slides were digitized by whole slide scanning. We used a Definiens Developer Tissue Studios as software for analysis. We configured necessary parameters in combination with 'machine learning' to identify pathological aberrations. A significant difference between AM- and non-AM-affected tissues was found for calretinin (AM 0.55% vs. non-AM 1.44%) and MAP2 (AM 0.004% vs. non-AM 0.07%) staining measurements and software-based evaluations. In contrast, S100β and GLUT1 staining measurements and software-based evaluations showed no significant differences between AM- and non-AM-affected tissues. However, no difference was found in comparison of suction biopsies with resections. Applying machine learning via an ensemble voting classifier, we achieved an accuracy of 87.5% on the test set. Automated diagnosis of AM by applying digital pathology on immunohistochemical panels was successful for calretinin and MAP2, whereas S100β and GLUT1 were not effective in diagnosis. Our method suggests that software-based approaches are capable of diagnosing AM. Our future challenge will be the improvement of efficiency by reduction of the time-consuming need for large pre-labelled training data. With increasing technical improvement, especially in unsupervised training procedures, this method could be helpful in the future.

The advances of genetics research on Hirschsprung's disease

Hirschsprung's disease (HSCR) is a rare and complex congenital disorder characterized by the absence of the enteric neurons in lower digestive tract with an incidence of 1/5 000. Affected infant usually suffer from severe constipation with megacolon and distended abdomen, and face long-term complications even after surgery. In the last 2 decades, great efforts and progresses have been made in understanding the genetics and molecular biological mechanisms that underlie HSCR. However, only a small fraction of the genetic risk can be explained by the identified mutations in the previously established genes. To search novel genetic alterations, new study designs with advanced technologies such as genome/exome-wide association studies (GWASs/EWASs) and next generation sequencing (NGS) on target genes or whole genome/exome, were applied to HSCR. In this review, we summaries the current development of the genetics researches on HSCR based on GWASs/EWASs and NGS, focusing on the newly discovered variants and genes, and their potential roles in HSCR pathogenesis.

Diagnostic Accuracy of Combined Acetylcholinesterase Histochemistry and Calretinin Immunohistochemistry of Rectal Biopsy Specimens in Hirschsprung's Disease

BACKGROUND

Acetylcholinesterase (AchE) histochemistry has been established as an accurate diagnostic tool for Hirschsprung's disease (HD). In addition, calretinin immunohistochemistry is also reported as a reliable and adjunctive method to diagnose HD. We investigated the diagnostic value of combined AchE histochemistry and calretinin immunohistochemistry in rectal suction biopsies from HD and non-HD patients.

METHODS

We retrospectively reviewed 99 rectal suction biopsy specimens including 4 repeat biopsies from 95 patients (34 HD and 61 non-HD). Each specimen was evaluated with hematoxylin-eosin, AchE histochemistry, and calretinin immunohistochemistry.

RESULTS

Of 95 patients, only 21 (22.1%) showed some ganglion cells. All 61 non-HD cases revealed no abnormal AchE-positive fibers. Of 34 HD patients, 32 exhibited abnormal AchE fibers, but 2 showed no stained fibers. None of the tissues from the HD patients exhibited calretinin immunoreactivity. Test sensitivity and specificity of AchE histochemistry alone were 93.5% and 100.0%, respectively, while calretinin immunohistochemistry were 100.0% and 85.2%, respectively.

CONCLUSIONS

AchE histochemistry is a good diagnostic method for HD, if feasible, and a combination of AchE histochemistry and calretinin immunohistochemistry will help increase the accuracy of the diagnosis of HD.

Development of Nerve Fibre Diameter in Young Infants With Hirschsprung Disease

OBJECTIVES

Finding thickened nerve fibres is one of the key elements in the diagnosis of Hirschsprung disease (HD); however, its value at different ages remains uncertain. Nerve fibre diameters <40 μm can be observed in infants younger than 8 weeks, despite the presence of HD. The aim of this study was to identify a change in maximum nerve fibre diameter in HD patients, measured before and after 8 weeks of age.

METHODS

Nerve fibre diameter was retrospectively evaluated in tissue of 20 infants treated for definite HD. Rectal suction biopsies (RSBs) obtained within the first 8 weeks of life (T1) and resected bowel obtained during primary surgery at an average of 24.7 weeks (T2), were assessed. The 2 thickest nerve fibre diameter recordings at T1 and T2 were compared in each subject, to examine changes in nerve trunk diameter with increasing age.

RESULTS

In 13 cases (65%), nerve fibre diameters were ≥40 μm at T1 and T2. Six subjects (30%) had nerve trunk diameters <40 μm at T1; however, they experienced diameter increases to ≥40 μm by T2. Thus, at T2, 19 subjects (95%) had diameter recordings ≥40 μm. Nerve fibre diameter in the remaining case (5%) stayed consistent at <40 μm at T1 and T2, despite the presence of HD.

CONCLUSIONS

After the first 8 weeks of life, nerve fibre measurements appear to be associated with HD. Measuring the 2 thickest nerve fibres can support typical HD diagnosis criteria beyond 8 weeks of age, but is not superior to histopathological confirmation of aganglionosis.

Is hematoxylin-eosin staining in rectal mucosal and submucosal biopsies still useful for the diagnosis of Hirschsprung disease?

Background

Hematoxylin-eosin (HE) staining of a full-thickness rectal wall fragment is classically used for the diagnosis of Hirschsprung disease (HD). However, this technique requires large fragments for a better diagnosis. Additionally, the histochemical and immunohistochemical methods of staining small fragments of rectal mucosal and submucosal biopsies are not available in all centers. Therefore, the possibility of diagnosing HD through HE staining in these biopsies could be a valuable alternative for centers that do not have more specific techniques. The objectives of the current investigation were to evaluate the concordance of the results obtained by HE staining and the calretinin method with acetylcholinesterase (AChE) activity in fragments of mucosa and submucosa in the diagnosis of HD.

Methods

For this study, 50 cases from our laboratory were selected. The tissue material was embedded in paraffin. Sixty levels of each fragment were utilized for HE, and the other 3 levels were used for calretinin. These slides were analyzed under the microscope, photographed and classified as either positive for HD when no ganglion cells were found with nerve trunks present or as negative when ganglion cells were found. The results from reading the slides were compared with those of AChE.

Results

Of the 50 cases evaluated by the HE technique, only 5 contradicted the diagnosis based on AChE, with a Kappa value of 0.800 and an accuracy of 90%. In the comparison between calretinin and AChE, 8 cases were discordant, with a Kappa value of 0.676 and an accuracy of 84%.

Conclusions

The concordance of results from AChE and HE methods was satisfactory, allowing for the potential use of the HE method for fragments of mucosa and submucosa as a valid alternative in the diagnosis of HD. The immunohistochemical technique of calretinin did not show good agreement with the AChE activity in our study.

Utility of Peripherin Versus MAP-2 and Calretinin in the Evaluation of Hirschsprung Disease

Hirschsprung disease (HD) is a congenital malformation resulting from the lack of migration of ganglion cells in the colon. The absence of ganglion cells in rectal suction biopsies aids in diagnosis, but evaluation of these small biopsies can be difficult. In this study, we compare the microtubule-associated protein-2 (MAP-2), calretinin, and peripherin immunohistochemical stains in 237 selected biopsies performed to rule out HD. By H&E stain, a total of 78 biopsies had ganglion cells, whereas 83 biopsies had no ganglion cells, and an additional 76 biopsies were equivocal for ganglion cells. Of the 78 biopsies with ganglion cells, MAP-2 was positive in 73 (94%), calretinin in 76 (97%), and peripherin in 78 (100%). Of the 83 biopsies with no ganglion cells, calretinin and peripherin highlighted nerve fibrils and ganglion cells, respectively, in 3 biopsies, whereas MAP-2 was positive in only 1 biopsy. Of the 76 biopsies equivocal for ganglion cells, 16 cases were positive by all 3 stains, an additional case by both calretinin and peripherin, and 2 cases by peripherin only. All of the newly positive biopsies were from patients without HD. This study demonstrates that peripherin is superior in helping to rule out HD in these small biopsies, highlighting ganglion cells in virtually all cases with ganglion cells, whereas MAP-2 and calretinin are less sensitive for identification of ganglion cells and nerve fibrils, respectively. In patients with HD, a panel using calretinin and peripherin with or without MAP-2 may be most helpful in identifying transition zones.

Choline Transporter Immunohistochemistry: An Effective Substitute for Acetylcholinesterase Histochemistry to Diagnose Hirschsprung Disease With Formalin-fixed Paraffin-embedded Rectal Biopsies

Acetylcholinesterase enzymatic histochemistry (AChE EHC), which highlights abnormal cholinergic nerves in the mucosa of aganglionic bowel, has been used for decades to evaluate rectal biopsies for Hirschsprung disease (HSCR). While useful diagnostically, AChE EHC is not compatible with conventional formalin-fixed and paraffin-embedded (FFPE) tissues and is not widely available. The choline transporter (ChT) is a putative alternative marker of cholinergic nerves. ChT immunohistochemistry (IHC) was investigated using FFPE biopsies and resections from patients with confirmed HSCR, as well as appropriate non-HSCR controls. ChT immunostaining was effective at identifying cases with HSCR and qualitatively similar to AChE EHC on frozen section. Among 3 pathologists, the diagnostic positive and negative predictive values based on ChT IHC ranged from 0.84-0.94 and 0.85-0.89, respectively, with good inter-observer agreement (Cohen kappa = 0.70-0.90). ChT IHC was useful in unusual scenarios in which calretinin (CR) IHC failed to correctly identify patients with HSCR. In 10 cases of short-segment HSCR, abnormal ChT+ mucosal innervation was present through the entire aganglionic segment and into portions of the TZ with submucosal nerve hypertrophy. In contrast, mucosal CR IHC was retained in the TZ and adjacent aganglionic bowel, which could lead to misinterpretation of a biopsy as ganglionic bowel. Indeed, 6 such patients were identified with paradoxical CR-positive mucosal innervation in their diagnostic biopsies. ChT IHC was interpreted as unequivocal HSCR in these cases, and HSCR was confirmed on resection. In summary, ChT IHC in FFPE tissue demonstrates high positive and negative predictive values for HSCR, is superior to CR IHC in a subset of cases, and can be incorporated into routine practice without the need for specialized techniques.

The evaluation of rectal mucosal punch biopsy in the diagnosis of Hirschsprung's disease: a 30-year experience of 954 patients

PURPOSE

For 30 years, we have consecutively performed rectal mucosal punch biopsy to diagnose Hirschsprung's disease. The aim of this study was to evaluate the safety of our technique.

METHODS

Patients with suspected Hirschsprung's disease who underwent punch biopsy, including our original "K-PUNCH" method using an S-moid forceps and non-specific blood-collecting tube at our department and branch hospital between April 1986 and March 2016 were included in the present study. Our punch biopsy technique is characterized by excellent visibility and a direct grasping sensation. The backgrounds and complications of the patients were retrospectively investigated.

RESULTS

During this period, 954 patients (median age 4 months; range 1 day-73 years) underwent punch biopsy. Although there were no cases of severe complications (i.e., rectal perforation, infection or full-thickness biopsy), one (0.1%) of the 954 cases in the early period showed liver dysfunction and required transfusion due to bleeding. In addition, inappropriate specimens were obtained in 37 patients (3.9%).

CONCLUSION

Punch biopsy including the "K-PUNCH" method is considered safe and feasible and is associated with a low rate of complications and inappropriate specimen harvesting among patients of all ages. Comorbidities, including the potential for hemorrhage, should always be considered.

Regenerative capacity of the enteric nervous system: is immaturity defining the point of no return?

BACKGROUND

Intestinal obstruction in newborns is associated with intestinal motility disorders after surgery. Alterations in the enteric nervous system (ENS) might cause abnormal peristalsis, which may then result in intestinal motility disorders. We aimed to quantify alterations in the myenteric plexus after a ligation and to test if these alterations were reversible.

METHODS

Small intestines of chicken embryos were ligated in ovo at embryonic day (ED) 11 for either 4 d (ED 11-15) or 8 d (ED 11-19). Both treated groups and control group were sacrificed and intestinal segments examined by means of both light and electron microscopy.

RESULTS

The number of proximal myenteric ganglia increased (ED 19, 30.7 ± 3.16 versus 23.1 ± 2.03; P < 0.001) in the 8-d ligature group but had values similar to the control group in the 4-d ligature group. The size distribution was skewed toward small ganglia in the 8-d ligature group (ED 19, 83.71 ± 11.60% versus 3.88 ± 4.74% in the control group; P < 0.001) but comparable with the control group in the 4-d ligature group. Subcellular alterations in the 4-d ligature group were reversible.

CONCLUSIONS

The pathologic alterations in the ENS were fully reversible in the 4-d ligature group. This reversibility might be linked to the degree of immaturity of the ENS.

Current practice patterns of rectal suction biopsy in the diagnostic work-up of Hirschsprung's disease: results from an international survey

PURPOSE

The diagnosis of Hirschsprung's disease (HD) was revolutionized by the introduction of rectal suction biopsy (RSB), allowing specimens to be taken without general anesthesia on the ward or as an out-patient procedure. However, insufficient tissue samples are not uncommon, and subsequently histopathologists often remain reluctant to confirm the presence or absence of enteric ganglion cells merely on the basis of submucosal RSBs. The aim of this study was to evaluate the current usage of RSB in the diagnostic work-up of HD based on an international survey.

METHODS

A 15-item questionnaire was distributed among participants and faculty members at the 21st International Meeting of the Pediatric Colorectal Society.

RESULTS

Eighty-seven pediatric surgeons from 30 countries completed the anonymous survey (response rate 70.2 %), grouped into 68 (78.2 %) staff surgeons and 19 (21.8 %) trainees, with a median work experience of 18 years (range 2-45 years). Of these, 74 (85.1 %) use RSB in the diagnostic work-up of patients with suspected HD, whereas 13 (14.9 %) prefer open full-thickness biopsy under general anesthesia. In total, 47 (63.5 %) respondents perform ≥20 RSBs (range 3-100 RSBs) per year. Five different RSB instruments were reported, the most common ones being rbi2 (65.0 %), Solo-RBT (15.0 %) and multipurpose suction biopsy kit (8.3 %). Only 22 (29.7 %) of the respondents use a defined negative suction pressure, with a median of 10 mL air (range 6-25 mL air). The most proximal reported biopsy site was located at a median of 2 cm (range 1-15 cm) above the pectinate line and a median of 2 (range 1-5) specimens are routinely taken, mainly from the posterior rectal wall. Insufficient tissue samples with need for repeat RSB were encountered in a median of 10 % (range 0-40 %). Most frequently used staining methods for rectal biopsies are hematoxylin/eosin (75.9 %), acetylcholinesterase (73.6 %), and calretinin (33.3 %). Overall, 36 (48.6 %) respondents had experienced RSB-related complications, including self-limiting rectal blood loss (n = 28), persistent rectal bleeding requiring blood transfusion (n = 9) and rectal perforation requiring surgical intervention (n = 7).

CONCLUSIONS

Although RSB is considered to be today's gold standard for the diagnosis of HD, many aspects of its current usage are lacking consensus. Therefore, a prospective multi-center study or larger global audit appears warranted to identify if the present survey reflects common surgical practice and to establish universal standards for RSB.

Modified Rapid AChE Method (MRAM) for Hirschsprung Disease Diagnosis: A Journey from Meier-Ruge Until Now

Hirschsprung disease (HSCR) can be diagnosed using a variety of histological and immunohistochemical methods and stains. Because of the nature of the condition and the need for a rapid diagnostic confirmation, those methods with high accuracy and fast turnaround times are preferred. The authors of this paper have used rapid acetylcholinesterase (AChE) immunohistochemistry in conjunction with standard H&E in order to optimize diagnostic accuracy, and present a modified rapid AChE method (MRAM) that has been successfully utilized for over 20 years. The authors also present a list of over 30 different methods and stains that have been proposed for Hirschsprung disease diagnosis.

Acetylcholinesterase histochemistry (AChE)--A helpful technique in the diagnosis and in aiding the operative procedures of Hirschsprung disease

Background

Hirschsprung’s disease (HD) is an anomaly characterized by the absence of myenteric and submucosal ganglion cells (GC) in the distal alimentary tract. Diagnosis of HD is made by the absence of GC and missing out on even a single ganglion cell can be very devastating. Acetylcholinesterase (AChE) histochemistry, done on frozen sections is said to be a very useful ancillary technique in the diagnosis and in aiding the operative procedures of HD.

Methods

To assess this, 73 samples from 42 suspected/known cases of HD were subjected to frozen section analysis with rapid haematoxylin and eosin, toluidin blue stain along with AChE histochemistry. The remnant sample was paraffin embedded for routine haematoxylin and eosin staining.

Results

On frozen section analysis, 33 samples showed absence of ganglion cells, AChE histochemistry showed a positive staining pattern in 17 samples and paraffin embedded routine, H&E stained sections showed absence of ganglion cells in 19 samples. Sensitivity and specificity of both tests ie frozen section rapid H&E/AChE histochemistry in the diagnosis of HD, were calculated taking paraffin embedded H&E stained sections as the gold standard. Sensitivity of frozen section rapid H&E in the diagnosis of HD is 57.57 % and specificity is 79.10 %. The p-value is <0.0001, which is significant. The sensitivity of AChE histochemistry in the diagnosis of HD is 90.47 % and specificity is 96.36 %. The p-value is <0.0001, which is significant.

Conclusions

Acetylcholineesterase (AChE) histochemistry is a very useful ancillary technique in the diagnosis and in aiding the operative procedures of HD. It acts as a double check in the diagnosis of HD.

Rectal suction biopsy for the diagnosis of Hirschsprung's disease: a systematic review of diagnostic accuracy and complications

PURPOSE

Rectal suction biopsy (RSB) combined with acetylcholinesterase (AChE) staining is currently the gold standard for the diagnosis of Hirschsprung's disease (HD). However, some pathologists are still reluctant to diagnose HD in RSBs as it requires thick submucosal tissue to confirm the absence of ganglion cells. Furthermore, insufficient specimens and adverse events have been reported. The objective of this study was to determine the diagnostic accuracy and incidence of complications of RSBs in patients suspected of HD based on a systematic review of the published literature.

METHODS

A literature-based search for relevant publications was conducted using multiple online databases. Staining for AChE/hematoxylin and eosin should have been used to evaluate RSBs. The number of true-positive, false-positive, true-negative and false-negative results was recorded and data on RSB-related complications was extracted. Pooled incidence rates and odds ratios (ORs) with 95% confidence intervals (CI) were calculated using standardized statistical methodology.

RESULTS

Fifty-eight studies met defined inclusion criteria, reporting a total of 14,053 RSBs. The median cohort size consisted of 72 patients (range 1-766) with a median age of 14.4 months (range 1 day-66 years) at time of biopsy. In 89.93% (CI 89.11-90.70%), RSB provided adequate tissue for the diagnosis of HD. Insufficient specimens were obtained in 10.07% (CI 9.30-10.89%) and in 8.46 % (CI 7.55-9.46%) RSB was repeated. The incidence of HD was 19.13% (CI 18.25-20.03%). Mean sensitivity of RSB was 96.84% (CI 95.57-97.47%) and mean specificity was 99.42% (CI 99.17-99.57%). The overall complication rate was 0.65% (CI 0.46-0.91%) with persistent rectal bleeding requiring blood transfusion in 0.53% (CI 0.36-0.77%), bowel perforation in 0.06% (CI 0.02-0.18%) and pelvic sepsis in 0.06% (CI 0.02-0.18%). Complications were significantly more frequent in newborns and infants compared to older children (OR 9.00 [CI 4.75-17.07], p < 0.0001).

CONCLUSIONS

RSB combined with AChE staining is a simple, safe and accurate method for the diagnosis of HD. The risk for RSB-related complications is higher in newborns and infants.

Reevaluation of acetylcholinesterase staining for the diagnosis of Hirschsprung disease and allied disorders

OBJECTIVES

Acetylcholinesterase (AChE) staining has become the gold standard for definitively diagnosing Hirschsprung disease (HD), although some pitfalls have been reported. We reevaluated a large series at our institute in order to validate the accuracy of AChE staining for detecting HD.

METHODS

A retrospective study of the rectal mucosal specimens of all of the children with suspected HD during a 13-year period was performed. The specimens were stained according to the modified Karnovsky-Roots method for AChE staining. The final diagnosis, prognosis, and management after the histopathological diagnosis were analyzed with a questionnaire sent to the patient's original hospital.

RESULTS

Three hundred and fifty-eight specimens were collected. One hundred twenty-two (34%) specimens were diagnosed as HD, 198 (55%) as nonHD, 25 (7%) as "undetermined," and 13 (4%) as "inappropriate." The non-HD group contained 190 (96%) specimens with a normal appearance and 8 (4%) specimens with suspected intestinal neuronal dysplasia (IND). Three hundred and six of 358 questionnaires were returned. The final diagnosis showed that no specimens first diagnosed as HD were identified as non-HD and vice versa, for a sensitivity and specificity of 100%. Four cases were finally diagnosed as chronic idiopathic intestinal pseudo-obstruction (CIIP) in the non-HD group. All of the patients with HD underwent radical surgery. Most non-HD patients were managed conservatively, although some continued to have constipation.

CONCLUSIONS

AChE staining is an accurate tool for differentiating between HD and non-HD with high sensitivity and specificity. CIIP can be included in cases of non-HD; therefore, careful follow-up is mandatory.

Immunohistochemical panel for the diagnosis of Hirschsprung's disease using antibodies to MAP2, calretinin, GLUT1 and S100

AIMS

The diagnosis of Hirschsprung's disease is currently based on the identification of aganglionosis and the presence of an increase in acetylcholinesterase-positive hypertrophic nerve fibres in the large bowel submucosa. However, acetylcholinesterase staining is laborious and requires a skilled technician. The aim of this study was to identify a method for diagnosing Hirschsprung's disease reliably using an immunohistochemical panel of recently proposed markers.

METHODS AND RESULTS

Sixty-nine specimens from 37 patients were evaluated. MAP2 and calretinin antibodies were shown to stain ganglia reliably in the submucosal and myenteric plexuses of normal tissue. By contrast, reduced staining of ganglia was observed in patients with Hirschsprung's disease. Staining for GLUT1 and S100 was used to evaluate the number and thickness of nerve fibres. Gain of GLUT1 and S100 expression was in contrast to the loss of calretinin and MAP2. Hypertrophic submucosal nerve fibres in Hirschsprung's disease develop a perineurium with a ring-like GLUT1 staining pattern similar in size and intensity to that observed in deeper subserosal tissue.

CONCLUSIONS

The diagnosis of Hirschsprung's disease using immunohistochemical panels could be as accurate as with conventional frozen section techniques. In particular, the use of a combination of markers for ganglia and hypertrophic nerve fibres highlighting a prominent perineurium in Hirschsprung's disease could be an alternative method.

Reversible small bowel obstruction in the chicken foetus

BACKGROUND

Ligation of the embryonic gut is an established technique to induce intestinal obstruction and subsequently intestinal atresia in chicken embryos. In this study, we modified this established chicken model of prenatal intestinal obstruction to describe (1) the kinetics of morphological changes, (2) to test if removal of the ligature in ovo is possible in later embryonic development and (3) to describe morphological adaptations following removal of the ligature.

MATERIALS AND METHODS

On embryonic day (ED) 11, small intestines of chick embryos were ligated micro surgically in ovo. In Group 1 (n = 80) gut was harvested proximal and distal to the ligation on ED 12-19. In Group 2 (n = 20) the induced obstruction was released on day 15 and gut was harvested on ED 16-19. Acetyl choline esterase staining was used as to assess resulting morphological changes.

RESULTS

A marked intestinal dilatation of the proximal segment can be seen 4 days after the operation (ED 15). The dilatation increased in severity until ED 19 and intestinal atresia could be observed after ED 16. In the dilated proximal segments, signs of disturbed enteric nervous system morphology were obvious. In contrast to this, release of the obstruction on ED 15 in Group 2 resulted in almost normal gut morphology at ED 19.

CONCLUSION

Our model not only allows the description of morphological changes caused by an induced obstruction on ED 11 but also-more important - of morphological signs of adaptation following the release of the obstruction on ED 15.

Predictive value of nerve trunk size in the neonate

PURPOSE

The diagnosis of Hirschsprung's disease (HD) remains challenging. The identification of ganglion cells is difficult and acetycholine esterase (AChE) staining can be subject to a great variability, particularly in the neonatal period (<8 weeks). Nerve trunks greater than 40 µm are considered to be predictive for HD. The aim of this study was to evaluate the usefulness of measuring nerve trunk size in the newborn with HD.

METHODS

Out of 292 biopsies 69 could be reanalyzed by three independent researchers. 40 µm was used as cutoff point for nerve trunk size. They were subdivided into three groups: (a) diagnosis of HD certain at the first biopsy, (b) no HD and (c) diagnosis of HD remains doubtful and re-biopsy taken.

RESULTS

In 87 % of group A nerve trunk size was ≥ 40 µm (SD 13.8). In 84 % of group B trunk size was < 40 µm (SD 16.2). In group C only 60 % of the patients showed a positive correlation between final diagnosis and nerve trunk size.

CONCLUSION

Using 40 µm as the cutoff point gave 13 % false-negative and 16 % false-positive cases. Measurement of the nerve trunk in the neonatal period does not seem to be a reliable method for detecting HD.

Does calretinin immunohistochemistry reduce inconclusive diagnosis in rectal biopsies for Hirschsprung disease?

Many difficulties occur during the evaluation of rectal biopsies for the diagnosis of Hirschsprung disease. We investigated whether the introduction of calretinin (CR) immunohistochemistry in a diagnostic panel could decrease the rate of inconclusive results. Data from 82 patients undergoing rectal biopsies before and after CR introduction were analyzed. Inconclusive results were obtained in 17 of 45 rectal biopsies (37.8%) in the series of cases before CR introduction and in 5 of 42 rectal biopsies (11.9%) in the series of cases after CR (P < 0.006). The inclusion of CR in the histopathologic panel may improve the diagnostic accuracy of Hirschsprung disease.

Calretinin-immunoreactive mucosal innervation in very short-segment Hirschsprung disease: a potentially misleading observation

Absent calretinin-immunoreactive (CRir) mucosal innervation in aganglionic rectal biopsies is considered a useful diagnostic finding for Hirschsprung disease. Analysis of a series of rectosigmoid resections from patients with short-segment (>2-cm aganglionic, n  =  9) and very short-segment (≤2-cm aganglionic, n  =  9) Hirschsprung disease demonstrates that CRir mucosal nerves extend into the proximal 1-2 cm of aganglionic bowel, where their presence in distal rectal biopsies could complicate diagnosis of very short-segment disease. Indeed, retrospective analysis of preoperative, aganglionic, distal rectal biopsies from 4 of 9 patients with very short-segment Hirschsprung disease revealed CRir mucosal innervation. Accurate diagnosis was possible based on generous histopathological submucosal sampling to exclude ganglion cells and the presence of abundant large-caliber submucosal nerves (more than 4 nerves >30 µm thick/×200 field or more than 2 nerves >40 µm thick/×200 field). Absent CRir mucosal innervation supports the diagnosis of Hirschsprung disease, but the presence of CRir mucosal nerves does not exclude aganglionosis, especially in distal rectal biopsies from patients with very short-segment Hirschsprung disease.

Calretinin and microtubule-associated protein-2 (MAP-2) immunohistochemistry in the diagnosis of Hirschsprung's disease

BACKGROUND/PURPOSE

Identifying ganglion cells by rectal suction biopsy is a basic diagnostic tool for the diagnosis of Hirschsprung's disease (HD). However, the difficult interpretation of conventionally processed slides often necessitates ancillary staining methods. The aim of this study was to evaluate the usefulness of calretinin and microtubule-associated protein-2 (MAP-2) immunohistochemistry in the diagnosis of HD.

METHODS

We analyzed 52 rectal suction biopsy specimens (37 from 15 HD patients and 15 from 7 non-HD patients) for ganglion cells with calretinin and MAP-2 immunohistochemistry. We also analyzed full-thickness, frozen biopsy samples obtained from 15 HD patients who underwent surgery utilizing calretinin and MAP-2 immunohistochemistry.

RESULTS

Both calretinin and MAP-2 positively stained ganglion cells in the submucosal plexus of the ganglionic bowel but not aganglionic bowel. Calretinin usually stained ganglion cell cytoplasm and nuclei more intensely than MAP-2, which only stained cytoplasm. No nerve fiber staining in the submucosal layer was observed for either antibody. In 21.1% (11/52) of samples, calretinin and MAP-2 staining found ganglion cells which were reported not to have ganglion cells in the original surgical pathology reports. Immunohistochemical staining for calretinin using paraffin-embedded tissue sections after cryostat sections clearly demonstrated decreased staining intensity compared to MAP-2.

CONCLUSION

Calretinin and MAP-2 are useful diagnostic markers for diagnosing HD in rectal suction biopsies. These complementary methods could ameliorate the diagnostic difficulties associated with HD.

Hirschsprung Disease and Use of Calretinin in Inadequate Rectal Suction Biopsies

Context.—Up to 17% of all rectal suction biopsies performed in the evaluation of Hirschsprung disease are considered inadequate. In most instances, inadequate biopsies contain too little submucosa or are taken within the anal transition zone.

Objectives.—To examine the utility of calretinin stain in the workup of inadequate biopsies for patients with clinical suspicion of Hirschsprung disease.

Design.—A retrospective analysis was conducted of all rectal suction biopsies performed in the evaluation of Hirschsprung disease during the previous 12 years that were considered “inadequate.” Seventeen cases were identified, and Hirschsprung disease status was determined by clinical or surgical follow-up. Immunohistochemistry for calretinin was performed for all cases containing columnar mucosa, which were evaluated without knowledge of clinical course.

Results.—All 12 patients without Hirschsprung disease had calretinin-positive nerve fibers in the lamina propria or muscularis mucosae, and all 5 patients with Hirschsprung disease had no calretinin staining of nerves.

Conclusions.—In this retrospective series, calretinin immunohistochemistry correctly predicted outcome in all instances. Although the gold standard for the diagnosis of Hirschsprung disease in rectal suction biopsies remains the evaluation of ganglion cells in a hematoxylin-eosin staining with sufficient submucosa, calretinin immunohistochemistry is quite helpful in triaging further workup based on clinical suspicion.

Sudden unexpected early neonatal death due to undiagnosed Hirschsprung disease enterocolitis: a report of two cases and literature review

Hirschsprung enterocolitis (HEC) is an uncommon, albeit well known, complication of Hirschsprung disease (HD). It is multifactorial and can appear in different age groups, but is particularly important in the neonatal period where it is characteristically seen in full-term neonates. Two cases of HEC are reported that were diagnosed at post-mortem examination, which presented as early sudden neonatal death, with a review the literature on fatal Hirschsprung enterocolitis. Case 1 was a 4-day old male neonate who was found unwell, struggling to breath, and with green vomitus. He was taken to hospital and pronounced dead a short time later. According to the parents meconium was passed on the first day. Post-mortem examination demonstrated necrotizing enterocolitis with isolated bowel perforation. Histology disclosed unsuspected HD. Case 2 was a 2-day old male neonate who was found wheezing with green vomitus. He arrived floppy, cyanosed, and in shock at the hospital and died a few hours later. Meconium was not passed, according to the parents. Post-mortem examination revealed necrotizing enterocolitis. There was also recto-sigmoidal aganglionosis and acetylcholinesterase staining confirmed HD. HEC is a multifactorial and sometimes recurrent complication of HD which characteristically develops in full-term neonates. Presentation with early sudden neonatal death is rare but should be considered in the diagnostic work-up of sudden deaths in this age group.

A useful panel for the diagnosis of Hirschsprung disease in rectal biopsies: calretinin immunostaining and acetylcholinesterase histochesmistry

The pathological evaluation of rectal biopsies for the diagnosis of Hirschsprung disease has been a challenging issue. We analyzed prospectively the usefulness of calretinin immunostaining and acetylcholinesterase (AChE) histochesmistry in rectal biopsies for the diagnosis of Hirschsprung disease. Frozen tissue samples from 43 patients were used for AChE histochemistry and paraffin-embedded sections for calretinin immunohistochemistry and conventional histology (hematoxylin and eosin [H&E]). Activity for AChE, was demonstrated in 13 of 43 cases, and the absence of immunoreactivity for calretinin was observed in 14 of 43 cases. Conventional histology (H&E) did not reveal ganglion cells in 24 of 43 cases. The results on calretinin were in good agreement with AChE according to the κ index (0.946; P<.001) and presented significantly higher specificity (96.7×63.3; P<.002) and accuracy (97.6×74.4; P<.003) when compared with conventional histology (H&E). The final diagnosis of Hirschsprung disease was confirmed in 13 of 43 patients who were submitted to surgical treatment. The results of the present study indicate that calretinin can be a good tool in ruling out the diagnosis of Hirschsprung disease, by showing positive staining in ganglion cells and intrinsic nerve fibers, whereas AChE is useful in confirming the diagnosis of Hirschsprung disease, by revealing activity of this enzyme in hypertrophied nerve fibers. The association between calretinin and AChE can be a useful panel for the histopathologic evaluation of rectal biopsies for the diagnosis of Hirschsprung disease.

A new diagnostic scoring system to differentiate Hirschsprung's disease from Hirschsprung's disease-allied disorders in patients with suspected intestinal dysganglionosis

PURPOSE

To create a simple diagnostic scoring system to differentiate Hirschsprung's disease (HD) from Hirschsprung's disease-allied disorders (HAD) in patients with suspected intestinal dysganglionosis (IDs).

METHODS

Between 1998 and 2008, 967 patients with suspected intestinal dysganglionosis underwent surgical treatment at the pediatric surgery department of Tongji Hospital. The diagnosis of HD or HAD was confirmed by postoperative pathological examination. All patients underwent preoperative work-up including barium enema, anorectal manometry, and histochemical acetylcholinesterase staining of rectal mucosa. Known risk factors for IDs were recorded. The predicting score was calculated by summing the scores of the risk factors and three preoperative tests. The sensitivity, specificity, accuracy, positive predictive values, negative predictive values, positive likelihood ratios, and negative likelihood ratios of the predicting score were calculated. The cutoff score for predicting HD was determined using receiver operating characteristic (ROC) analysis. The accuracy of the predicting score was measured by the area under the ROC curve.

RESULTS

Failed or delayed passage of meconium, age <3 years and male gender were risk factors associated with HD. The area under the ROC curve of the predicting score was 0.927 (95 % confidence interval, 0.910-0.944). A predicting score of more than 5 was used as a cutoff for predicting HD. The scoring system achieved 83.1 % sensitivity, 89.5 % specificity, and 85.9 % accuracy in predicting HD.

CONCLUSION

Patients with a predicting score of more than 5 are more likely to be diagnosed with HD, whereas a score less than 5 are mostly indicative of HAD.

Transitional zone pull through: surgical pathology considerations

Incomplete resection of the transitional zone (TZ) between histologically normal and aganglionic bowel in Hirschsprung disease is a putative cause of postoperative dysmotility. A review of literature indicates that diverse histopathological indexes have been used to define the TZ, and validated and reproducible diagnostic criteria have not been established. As a consequence, the proximal margin of the TZ is difficult to delimit, and the length of the TZ in a given patient depends on the diagnostic criteria used. Seromuscular biopsies are inadequate to exclude TZ, as diagnostic indexes may involve only a portion of the bowel circumference or the submucosa. Most published investigations of postoperative outcome after a TZ pull through (TZPT) conclude that the latter can cause persistent obstructive symptoms, which necessitate reoperation. However, the results of these studies are difficult to translate into clinical practice because most lack appropriate controls, and the overwhelming majority provide inadequate histopathological descriptions for reference at the time of intraoperative frozen section analysis. At present, a conservative approach based on frozen section examination of the entire proximal margin of the resection to exclude obvious subcircumferential aganglionosis (contiguous gap between ganglia of more than one-eighth of the circumference), hypoganglionosis (continuous string of myenteric ganglia comprised of 1 or 2 ganglion cells without surrounding neuropil), or hypertrophic submucosal nerves (>2 nerves with widths ≥40 μm per high-power field) seems prudent. Well-controlled studies to correlate proximal margin histology, especially subtle anatomic or immunohistochemical changes, with postoperative outcome are needed.

Duhamel pull-through assisted by transrectal port: a hybrid natural orifice transluminal endoscopic surgery approach

One of the latest surgical innovations is natural orifice transluminal endoscopic surgery (NOTES). We hypothesize that the principles of NOTES could be applied to the laparoscopic Duhamel procedure. Between March 2008 and May 2010, 3 children underwent the laparoscopic Duhamel procedure assisted by transrectal NOTES. Three 5-mm transabdominal trocars were combined with a 12-mm transrectal trocar. We were able to safely apply the principles of NOTES, improving the performance of laparoscopic Duhamel pull-through using current instruments and technology. This new approach avoids the need of an extra transabdominal 12-mm trocar for the endoscopic stapler, allows an easier creation of a smaller rectal stump, and offers the possibility of an extra working port. This hybrid concept can be seen as a transition into the emerging field of NOTES in colorectal surgery.

Rectal suction biopsy to exclude the diagnosis of Hirschsprung disease

OBJECTIVES

Hirschsprung disease (HD) is defined as the absence of ganglion cells in the Meissner and Auerbach plexuses. Diagnosis depends on demonstrating the absence of ganglion cells in rectal biopsy specimens. Rectal suction biopsy is widely employed as the method of choice in obtaining such specimens. Classically, the diagnosis was made until the 1990s by using the Multipurpose Suction Biopsy Kit, or Rubin Tube. This device was replaced by the Model SBT-100 Suction Biopsy Kit as the exclusive device used to procure rectal tissue. Because the suction devices are known to occasionally yield tissue that is insufficient, the present study was undertaken to determine the efficacy of using this technique to make or exclude the diagnosis of HD.

METHODS

The last 50 biopsy sessions using the Multipurpose Suction Biopsy Kit and the first 46 sessions using the Model SBT-100 were included for review.

RESULTS

Both groups had similar yields (24%) of biopsy sessions with insufficient tissue to allow meaningful interpretation. The predictive value of rectal suction biopsy in excluding HD at the first biopsy session was 65%.

CONCLUSIONS

We conclude that HD can be excluded with a single rectal suction biopsy 65% of the time. A second biopsy session will exclude the diagnosis in an additional 11% of patients. Both devices yield biopsies of comparable quality and are equally useful in excluding the diagnoses of HD.

Constipation in childhood

Constipation in children is an often long-lasting pediatric functional gastrointestinal disorder with a worldwide prevalence varying between 0.7% and 29.6%, and estimated health-care costs of US$3.9 billion per year in the USA alone. The pathophysiology of childhood constipation is multifactorial and remains incompletely understood; however, withholding of stools, starting after an experience of a hard, painful, or frightening bowel movement is the most common cause found in children. A thorough medical history and physical examination, including a rectal examination in combination with a bowel diary, is sufficient in the majority of cases to diagnose constipation. The current standard treatment consists of education, toilet training, disimpaction, maintenance therapy and long-term follow-up. In the past decade, well-designed treatment trials in the pediatric population have emerged and long-term outcome studies have been completed. This Review summarizes the current knowledge of the clinical aspects of childhood constipation, including pathogenesis, diagnosis and treatment, with particular emphasis on the latest available data.

Nerve growth factor receptor immunohistochemistry has a limited additional value to diagnose Hirschsprung's disease

PURPOSE

The diagnosis of Hirschsprung's disease (HSCR) is based on the histopathological evaluation of rectal suction biopsies (RSB), using haematoxylin and eosin (H&E) stains and acetylcholinesterase (AChE) histochemistry. The use of different immunohistochemical markers, such as nerve growth factor receptor (NGFR), has been suggested to facilitate the diagnosis of HSCR. The aim of this study was to evaluate the addition of NGFR immunohistochemistry to diagnose HSCR.

METHODS

RSB from 23 HSCR patients and 16 patients investigated for, but not diagnosed with, HSCR were retrospectively reviewed. The histopathology report supported or did not support the diagnosis of HSCR.

RESULTS

In patients with HSCR, the primary biopsies confirmed the diagnosis in 21 of 23 cases with H&E staining, in 16 of 23 cases with AChE histochemistry, and in 8 of 23 cases with NGFR immunohistochemistry. Due to inadequate biopsies or equivocal interpretation, the biopsies were repeated in seven of the patients with HSCR and two patients underwent biopsies a third time. In the 16 patients investigated for but not diagnosed with HSCR, the three tests were normal in all cases.

CONCLUSION

We conclude that NGFR immunohistochemistry has limited additional value to diagnose HSCR.

Redo surgery in Hirschsprung disease: what did we learn? Unicentric experience on 70 patients

PURPOSE

This article is aimed at describing a series of 70 patients who underwent a redo pull-through in the period between January 1991 and January 2007 and to compare them with a series of consecutive patients with Hirschsprung disease who underwent a single pull-through.

METHODS

The notes were reviewed, and a comprehensive interview based on a disease-specific questionnaire for continence and quality of life was submitted to all eligible patients. We used a number of consecutive patients who underwent a single pull-through for Hirschsprung disease as control group.

RESULTS

Seventy patients were included. Residual aganglionosis in pulled-through bowel or retained aganglionic rectum represented the indications to reoperation in most cases. Intestinal obstruction represented the leading symptom in more than 60% of patients. We adopted either the endorectal pull-through, the Duhamel, or the Swenson procedure. Thirty-six patients were assessed for long-term outcome. One third experienced complications. Long-term continence was satisfactory in 70%. Enterocolitis, soiling, and perineal excoriations were complained by 30%. Excellent to good perspectives were described by 94%, and excellent to good cosmetic results by 22%. The only significant difference with control group (109 patients) involved cosmetic appearance, whereas soiling, although more frequent, could not be considered significantly increased.

CONCLUSIONS

Patients who experience failure of a pull-through must go through multiple procedures to achieve definitive results. Although overall outcome does not significantly differ from that of a single effective pull-through, great efforts should be made to minimize complications and avoid the need for a redo, which requires experienced surgeons and highly committed families for a longer course of the disease.

The histopathology of gastrointestinal motility disorders in children

Gastrointestinal motility disorders and chronic constipation are common pediatric problems. Symptoms of abdominal discomfort are frequently encountered in the daily practice of pediatricians and pediatric surgeons. Normal peristalsis depends on the interaction between muscles, nerve cells, and tendinous connective tissue of muscularis propria. Malfunction of any of these components results in a motility disorder. Aganglionosis, typically of the left distal colon, is the cause of Hirschsprung disease. Hypoganglionosis constitutes another gastrointestinal motility disorder. In hypoplastic hypoganglionosis, the number of nerve cells and the size of ganglia of the enteric nervous system are reduced, resulting in symptoms similar to aganglionosis. In intestinal neuronal dysplasia type B, submucous plexus development is disturbed. Immaturity of the enteric nervous system, but also ganglioneuromatosis, can be the underlying cause of chronic constipation. Chronic constipation may be caused by a myopathy. Aplasia or atrophy of the tendinous connective tissue of muscularis propria may cause desmosis, which may result in an aperistaltic syndrome. In severe chronic constipation, a histopathological diagnosis of the underlying cause is useful. In the diagnostic approach for most of these causes of chronic constipation, enzyme histochemistry is an efficient tool to complement conventional immunohistochemical and selected molecular technologies. An interdisciplinary approach of a gastrointestinal working group is beneficial in the management of these difficult patients.