The loss of calretinin expression indicates aganglionosis in Hirschsprung's disease

Clinical Relevance of Pathological Diagnosis of Hirschsprung's Disease with Acetylcholine-Esterase Histochemistry or Calretinin Immunohistochemistry

INTRODUCTION

Hirschsprung disease (HD) manifests as a developmental anomaly affecting the enteric nervous system, where there is an absence of ganglion cells in the lower part of the intestine. This deficiency leads to functional blockages within the intestines. HD is usually confirmed or ruled out through rectal biopsy. The identification of any ganglion cells through hematoxylin and eosin (H&E) staining rules out HD. If ganglion cells are absent, further staining with acetylcholine-esterase (AChE) histochemistry or calretinin immunohistochemistry (IHC) forms part of the standard procedure for determining a diagnosis of HD. In 2017, our Institute of Pathology at University Hospital of Heidelberg changed our HD diagnostic procedure from AChE histochemistry to calretinin IHC. In this paper, we report the impact of the diagnostic procedure change on surgical HD therapy procedures and on the clinical outcome of HD patients.

METHODS

We conducted a retrospective review of the diagnostic procedures, clinical data, and postoperative progress of 29 patients who underwent surgical treatment for HD in the Department of Pediatric Surgery, University of Heidelberg, between 2012 and 2021. The patient sample was divided into two groups, each covering a treatment period of 5 years. In 2012-2016, HD diagnosis was performed exclusively using AChE histochemistry (AChE group, n = 17). In 2017-2021, HD diagnosis was performed exclusively using calretinin IHC (CR group, n = 12).

RESULTS

There were no significant differences between the groups in sex distribution, weeks of gestation, birth weight, length of the aganglionic segment, or associated congenital anomalies. Almost half of the children in the AChE group, twice as many as in the CR group, required an enterostomy before transanal endorectal pull-through procedure (TERPT). In the AChE group, 4 patients (23.5%) required repeat bowel sampling to confirm the diagnosis. Compared to the AChE group, more children in the CR group suffered from constipation post TERPT.

DISCUSSION

Elevated AChE expression is linked to hypertrophied extrinsic cholinergic nerve fibers in the aganglionic segment in the majority of patients with HD. The manifestation of increased AChE expression develops over time. Therefore, in neonatal patients with HD, especially those in the first 3 weeks of life, an increase in AChE reaction is not detected. Calretinin IHC reliably identifies the presence or absence of ganglion cells and offers multiple benefits over AChE histochemistry. These include the ability to perform the test on paraffin-embedded tissue sections, a straightforward staining pattern, a clear binary interpretation (negative or positive), cost-effectiveness, and utility regardless of patient age.

CONCLUSIONS

The ability of calretinin IHC to diagnose HD early and time-independently prevented repeated intestinal biopsies in our patient population and allowed us to perform a one-stage TERPT in the first months of life, reducing the number of enterostomies and restoring colonic continuity early. Patients undergoing transanal pull-through under the age of 3 months require a close follow-up to detect cases with bowel movement problems.

Quantitative Spatial Analysis of Neuroligin-3 mRNA Expression in the Enteric Nervous System Reveals a Potential Role in Neuronal-Glial Synapses and Reduced Expression in Nlgn3R451C Mice

Mutations in the Neuroligin-3 (Nlgn3) gene are implicated in autism spectrum disorder (ASD) and gastrointestinal (GI) dysfunction, but cellular Nlgn3 expression in the enteric nervous system remains to be characterised. We combined RNAScope in situ hybridization and immunofluorescence to measure Nlgn3 mRNA expression in cholinergic and VIP-expressing submucosal neurons, nitrergic and calretinin-containing myenteric neurons and glial cells in both WT and Nlgn3^R451C mutant mice. We measured Nlgn3 mRNA neuronal and glial expression via quantitative three-dimensional image analysis. To validate dual RNAScope/immunofluorescence data, we interrogated available single-cell RNA sequencing (scRNASeq) data to assess for Nlgn3, Nlgn1, Nlgn2 and their binding partners, Nrxn1-3, MGDA1 and MGDA2, in enteric neural subsets. Most submucosal and myenteric neurons expressed Nlgn3 mRNA. In contrast to other Nlgns and binding partners, Nlgn3 was strongly expressed in enteric glia, suggesting a role for neuroligin-3 in mediating enteric neuron-glia interactions. The autism-associated R451C mutation reduces Nlgn3 mRNA expression in cholinergic but not in VIPergic submucosal neurons. In the myenteric plexus, Nlgn3 mRNA levels are reduced in calretinin, nNOS-labelled neurons and S100 β -labelled glia. We provide a comprehensive cellular profile for neuroligin-3 expression in ileal neuronal subpopulations of mice expressing the R451C autism-associated mutation in Nlgn3, which may contribute to the understanding of the pathophysiology of GI dysfunction in ASD.

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.

Diagnostic accuracy of calretinin and acetylcholinesterase staining of rectal suction biopsies in Hirschsprung disease examined by unexperienced pathologists

Rectal suction biopsy (RSB) is a gold standard for diagnosing Hirschsprung disease (HD). Calretinin staining of RSB is increasingly used by experienced pathologists due to non-complex examination and comparable diagnostic accuracy with acetylcholinesterase (AChE). However, the diagnostic accuracy of calretinin examined by unexperienced pathologists remains to be elucidated. Therefore, we aim to compare diagnostic accuracy of calretinin with AChE on RSB for diagnosing HD when examined by unexperienced pathologists. We prospectively analyzed sections from RSB stained with AChE + HE and calretinin. Blinded examination was done by five unexperienced pathologists (pathology residents) and three experienced pathologists (senior pediatric gastro-enterology pathologists) assessing for the presence of HD. Cases for the study included ones proven to be HD on resection specimens and cases without HD. Diagnostic accuracy was determined calculating area under the curve (AUC), sensitivity, specificity, likelihood ratio, and posttest probability. Fleiss’ kappa analysis was performed to assess interobserver agreement between reviewers. Eleven of 18 included patients (61%) were diagnosed with HD. Comparing the diagnostic accuracy of unexperienced pathologists, calretinin versus AChE + HE showed sensitivity of 80.0% versus 74.5% and specificity of 100% versus 65.4%, AUC of 0.87 (0.78–0.96) versus 0.59 (0.45–0.72). Unexperienced pathologists showed substantial agreement with calretinin (kappa 0.72 [0.61–0.84]) and fair agreement with AChE + HE (kappa 0.34 [0.23–0.44]). We found calretinin having higher diagnostic accuracy in diagnosing HD compared to AChE + HE when examined by unexperienced pathologists. Therefore, we recommend to use calretinin as the standard technique for staining RSB in diagnosing HD.

Submucosal Nerve Diameter in the Rectum Increases With Age: An Important Consideration for the Diagnosis of Hirschsprung Disease

INTRODUCTION

Hypertrophic submucosal nerves, defined as ≥40 µm in diameter, are considered supportive of a diagnosis of HSCR, but the effect of age on nerve diameter has not been well-studied. We sought to determine the distribution of the largest nerve diameter in ganglionic rectal biopsies and the significance of hypertrophic submucosal nerves in the diagnosis of Hirschsprung disease (HSCR) based on age.

METHODS

Rectal biopsies performed in the evaluation of HSCR were retrospectively reviewed from 179 patients (151 ganglionic biopsies, 28 aganglionic biopsies), and the diameter of the largest submucosal nerve was measured.

RESULTS

In non-Hirschsprung disease (non-HSCR) biopsies, submucosal nerve diameter increased with age. In patients <1 year, the average diameter was 34.1 ± 11.6 µm but increased to 50.8 ± 17.3 µm after 1 year of age. Submucosal nerves ≥40 µm in diameter were significantly associated with HSCR across all ages [HSCR = 25/28 (89.3%) vs non-HSCR = 59/151 (39.1%), p < 0.0001] and remained significant in patients <1 year of age [HSCR = 22/24 (91.7%) vs non-HSCR = 19/91 (20.9%), p < 0.0001].

CONCLUSIONS

The diameter of submucosal nerves increases with age, and ≥40 µm nerves are common after 1 year of age.

Characterization of the Transition Zone in Short Segment Hirschsprung Disease Using Calretinin Immunostaining

Introduction: The detailed expression pattern of calretinin immunohistochemistry in the transition zone (TZ) of Hirschsprung disease (HSCR) has not yet been reported. This study aims to examine the value of calretinin immunohistochemistry for more accurately determining the distal and proximal border of the TZ in short segment HSCR. Methods: Specimens of pull-through surgery from 51 patients with short form of HSCR were analyzed on two longitudinal strips using hematoxylin and eosin (H&E) staining and calretinin immunohistochemistry. Results: In all but two patients, the first appearance of calretinin expression was seen on mucosal nerve fibers before the appearance of any ganglion cells, indicating the distal border of the TZ. The maximum distance between the distal border of the TZ and the proximal border of the TZ, defined by ganglion cells in a normal density on H&E stained sections, a strong calretinin expression on mucosal nerve fibers and in >80% of submucosal and myenteric ganglion cells, with no nerve hypertrophy and absence of ganglionitis was 60 mm. Conclusion: The distal border of the TZ is characterized by calretinin positive intramucosal neurites in nearly all of short form of HSCR and not by calretinin expression on ganglion cells.

Increasing Trend of Calretinin-Positive Mucosal Innervation from Aganglionic Zone toward Transition Zone in Hirschsprung's Disease

INTRODUCTION

 Diagnosis of very short-segment Hirschsprung's disease (vsHD) by rectal suction biopsy is challenging as its aganglionic zone (AZ) overlaps with physiologic hypoganglionic zone and calretinin-positive mucosal nerves may extend from the transition zone (TZ) into AZ. We studied whether an increasing trend/gradient of calretinin-positive mucosal nerves along the distance from AZ toward TZ aids in diagnosis of HD.

MATERIALS AND METHODS

 In this study, 46 rectal suction biopsies from non-HD and HD, and 15 pull-through specimens from short-segment HD were evaluated by mucosal calretinin immunostain (CI) and image processing and analysis (IPA) to measure pixel count (PC, the percentage of calretinin stained pixels in the mucosa). Consecutive longitudinal sections of proximal AZ toward distal TZ in HD pull-through specimens were utilized as a vsHD surrogate model. First, we studied variability of mucosal CI in non-HD biopsies along the distance from dentate line. Second, we determined a cutoff point of mucosal CI by IPA that separated non-HD versus HD and applied this cutoff to longitudinal sections from proximal AZ to distal TZ segments in HD pull-through specimens. Third, we studied whether an increasing trend of mucosal CI was universally observed in HD pull-through.

RESULTS

 Our findings included a significant variability in PC along the biopsy distance in non-HD cases. Positive mucosal CI was found in proximal AZ in 6 (43%) of 14 HD pull-through, among which 1 case lacked submucosal nerve hypertrophy in the proximal AZ. All 14 HD pull-through cases showed an increasing trend/gradient of PC from AZ toward TZ.

CONCLUSION

 Based on our findings, the presence or absence of mucosal CI positivity and submucosal nerve hypertrophy may not reliably diagnose vsHD in rectal suction biopsy. While we acknowledge that the density of mucosal innervation in variable contexts and anatomical locations is unknown and yet to be explored, our study suggests that an increasing trend of positive mucosal CI from AZ toward TZ by IPA might prove to be a useful tool for the diagnosis of vsHD in the future.

Critical diagnoses in paediatric gastrointestinal diseases

Gastrointestinal biopsies represent an increasing proportion of the paediatric pathologist's workload, an increase fundamentally due to an expansion of the understanding of the basic clinical, molecular, genetic, and histopathological features of paediatric gastrointestinal disorders. The histological interpretation of endoscopically retrieved gastrointestinal biopsies in children requires a unique set of diagnostic expertise and detailed knowledge of various gastrointestinal disorders that have a predilection for the paediatric population. This article's major role is to highlight the unique problems inherent to paediatric gastrointestinal disorders that require immediate communication with the paediatric surgeon or the gastroenterologist. For this, we tried to cover the most important diseases that a paediatric pathologist might encounter in daily practice. Some of these diseases are relatively rare, such as microvillous inclusion disease and tufting enteropathy, but some are more common such as eosinophilic disorders and inflammatory bowel disease. Awareness of the histopathological features of these diseases, particularly those that are relatively uncommon, is crucial to spare the patient a lengthy and costly evaluation. We made a particular effort to abundantly reference this article should the reader wish to expand on the content of any section.

Diagnostic Role of Calretinin in Suspicious Cases of Hirschsprung's Disease

Background Hirschsprung's disease (HD) is a developmental disorder of the intrinsic component of the enteric nervous system. It is characterized by the absence of ganglion cells in the myenteric and submucosal plexus. Histopathological diagnosis becomes difficult many times due to submucosal ganglionic cells are not easily identifiable. Aims and objective The aim of this study was to examine the clinical and histopathological features of HD and to establish the utility of calretinin staining to diagnose the case of suspicious HD. Materials and methods After taking necessary informed consent, we studied 41 cases in which clinical suspicion of HD had been made, in a study duration of three years (July 2017-June 2020). Open biopsies were taken from spastic segment, transition zone and dilated segment. Histopathological diagnosis had been made in three categories: HD, no Hirschsprung's disease (NHD) and suspicion of HD. Post histopathological diagnosis calretinin immunohistochemistry (IHC) was applied to all cases and interpretations were noted. Results On the basis of histopathological findings, 25 cases were diagnosed as HD, nine cases were marked for suspicion for HD and seven cases as NHD. After evaluating calretinin IHC on the suspicious case, total of 30 cases were confirmed as HD while the remaining 11 cases were confirmed as NHD. Twenty-four patients of HD were males while the remaining six cases were females. The age of patients ranged from four days to 10 years. Median age six days while 22 patients were in the neonatal period. Conclusion Calretinin immunostaining is a useful modality in diagnosing suspicious cases of HD. Its results are easy to interpret by less experienced pathologist with accuracy.

Immunohistochemistry-based comparative study in detection of Hirschsprung's disease in infants in a Tertiary Care Center

BACKGROUND:

Hirschsprung's disease (HD) is the major cause of pediatric intestinal obstruction with a complex pattern of inheritance. The absence of ganglion cells along with an analysis of hypertrophy and hyperplasia of nerves in the nerve plexus of submucosa and muscularis mucosae is regarded as a potential hallmark for its diagnosis.

AIMS AND OBJECTIVES:

This study was undertaken to ascertain the (1) clinical profile, (2) mode of presentation, and (3) to compare the role of calretinin immunostaining with acetylcholinesterase in the diagnosis of HD.

MATERIALS AND METHODS:

This prospective and observational study was conducted in the Department of Pathology, IPGME & R from June 2014 to May 2015. One hundred and four patients clinically and radiologically diagnosed with HD underwent surgery were included in the study. The data of every patient including age, sex, and presenting symptoms were recorded. Eventually, histopathological, calretinin, and acetylcholinesterase immunohistochemical examination were done.

RESULTS:

Total numbers of cases studied were 104, which aged between 0 days and 365 days. Male preponderance (76.92%) was noted. The overall sensitivity, specificity, positive, and negative predictive value of acetylcholinesterase were 100%, 86.44%, 84.91%, and 100%, respectively. The concordance of detection of ganglion cells and nerve fibers, and thereby diagnosis of Hirschsprung's and non-HD using calretinin and the gold standard was statistically in strong agreement (κ = 0.749, 95% confidence interval: 0.635–0.863).

CONCLUSIONS:

Calretinin stands out as the single and indispensable tool that differentiates HD from other mimickers.

Innervation of the entire internal anal sphincter in a mouse model of Hirschsprung's disease: a first report

BACKGROUND

Impaired function of the internal anal sphincter (IAS) may be implicated in postoperative obstructed defecation (POD) that may complicate Hirschsprung's disease (HD) patients. While innervation of part of the IAS in HD has been reported, accurate details based on anatomic landmarks that can explain the clinical morbidity seen in POD are lacking, and there appear to be no studies that specifically document the innervation of the "entire" IAS in HD. We used endothelin receptor-B knockout mice to represent HD (HD-mice) and C57B6 wild mice as controls (C-mice) to investigate the innervation of the entire IAS to assess the pathophysiology of POD experimentally.

METHODS

The end-point of the longitudinal muscle layer was used to define the border between the IAS and the circular muscle layer (CML). Specimens of anorectum from HD- and C-mice were immunostained with PGP 9.5 and S100 as general nerve markers, nNOS and VIP as parasympathetic nerve markers, TH as a sympathetic nerve marker, and calretinin as a reliable diagnostic marker for HD. Immunostained cells/fibers were quantified using ImageJ.

RESULTS

On fluorescence microscopy, PGP 9.5, nNOS, and calretinin were significantly lower in the IAS of HD-mice than in C-mice (p < 0.05, respectively), while there were no significant differences between HD-mice and C-mice for S100, VIP, or TH.

CONCLUSION

We are the first to confirm that the expression of histochemical markers of innervation is abnormal throughout the "entire" IAS in HD-mice. Application of this finding may be beneficial for preventing POD and requires further research.

Malformations, choristomas, and hamartomas of the gastrointestinal tract and pancreas

Congenital and hamartomatous lesions of the gastrointestinal tract cause diagnostic challenges for surgical pathologists. Many of these are merely histologic curiosities, whereas others have substantial clinical implications because they herald cancer syndromes or associated anomalies. Although a comprehensive discussion of all developmental abnormalities that can occur in the gastrointestinal tract is beyond the scope of a single manuscript, some entities are more likely to be encountered by surgical pathologists, have important clinical consequences, or pose diagnostic difficulties. The purpose of this review is to discuss the more common malformations and choristomas, as well as hamartomatous lesions that may be clinically important due to their risk for cancer development, frequent associations with heritable cancer syndromes and other anomalies, or potential to simulate other entities.

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.

Meconium Peritonitis: A Case Study

Meconium peritonitis is a sterile chemical peritonitis preceded by bowel perforation, resulting in meconium leakage and subsequent inflammatory cascade within the peritoneal cavity. The presentation can range from simple failure of the neonate to pass meconium to complications such as persistent pulmonary hypertension, lung hypoplasia, and systemic inflammatory syndrome. The purpose of this article is to review a case of meconium peritonitis while considering its etiology, diagnosis, management, and multidisciplinary team care.

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.

Characterization and transplantation of enteric neural crest cells from human induced pluripotent stem cells

The enteric nervous system (ENS) is recognized as a second brain because of its complexity and its largely autonomic control of bowel function. Recent progress in studying the interactions between the ENS and the central nervous system (CNS) has implicated alterations of the gut/brain axis as a possible mechanism in the pathophysiology of autism spectrum disorders (ASDs), Parkinson's disease (PD) and other human CNS disorders, whereas the underlying mechanisms are largely unknown because of the lack of good model systems. Human induced pluripotent stem cells (hiPSCs) have the ability to proliferate indefinitely and differentiate into cells of all three germ layers, thus making iPSCs an ideal source of cells for disease modelling and cell therapy. Here, hiPSCs were induced to differentiate into neural crest stem cells (NCSCs) efficiently. When co-cultured with smooth muscle layers of ganglionic gut tissue, the NCSCs differentiated into different subtypes of mature enteric-like neurons expressing nitric oxide synthase (nNOS), vasoactive intestinal polypeptide (VIP), choline acetyltransferase (ChAT) or calretinin with typical electrophysiological characteristics of functional neurons. Furthermore, when they were transplanted into aneural or aganglionic chick, mouse or human gut tissues in ovo, in vitro or in vivo, hiPSC-derived NCSCs showed extensive migration and neural differentiation capacity, generating neurons and glial cells that expressed phenotypic markers characteristic of the enteric nervous system. Our results indicate that enteric NCSCs derived from hiPSCs supply a powerful tool for studying the pathogenesis of gastrointestinal disorders and brain/gut dysfunction and represent a potentially ideal cell source for enteric neural transplantation treatments.

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.

Rectal suction biopsy with calretinin immunohistochemistry in patients suspected with residual aganglionosis after operation for Hirschsprung disease

INTRODUCTION

This study investigates the use of rectal suction biopsy (RSB) with calretinin immunohistochemical staining (CIS) in patients suspected of having abnormally innervated bowel after pull through operation for Hirschsprung disease (HD).

METHOD

This study was conducted in Children's Hospital 2, Ho Chi Minh City from January 2015 through June 2016. Patients suspected with abnormally innervated bowel after pull through operation for HD were submitted for a RSB with CIS. Following histological results, the patients underwent an appropriate treatment (redo pull through operation or non-operative medical management) and followed up at least 6 months to evaluate their outcomes.

RESULTS

Ten patients were enrolled in our study. The median age was 5.6 (range 1.4-20) years. The diagnosis of normally innervated bowel was made in five patients by showing positive reactivity of CIS on RSB, whereas five others were diagnosed with abnormally innervated bowel. Final diagnosis of the five latter patients was confirmed by analyses of the resected bowel after a redo pull through operation (including 4 cases with residual aganglionosis and one case with transition zone bowel).

CONCLUSIONS

RSB with CIS is a reliable and simple method for diagnosis of abnormally innervated bowel after pull through operation for HD.

LEVEL OF EVIDENCE

III TYPE OF STUDY: Study of diagnostic test (evaluate the effectiveness of a diagnostic test or outcome assessment).

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.

A critical appraisal of the morphological criteria for diagnosing intestinal neuronal dysplasia type B

Intestinal neuronal dysplasia type B is a controversial entity expressed by complex changes in the enteric nervous system. Diagnosis depends on rectal biopsy histopathology and diagnostic criteria, both qualitative and quantitative, have changed over time, hindering the diagnostic practice. We analyzed the morphological criteria for the histological diagnosis of intestinal neuronal dysplasia type B in a series of patients with intestinal neuronal dysplasia type B according to the 1990 Frankfurt Consensus criteria and verified the applicability of the numerical criteria proposed by Meier-Ruge et al in 2004 and 2006. Qualitative criteria adopted for the histological diagnosis of intestinal neuronal dysplasia type B included hyperplasia of the submucous plexus with hyperganglionosis and hypertrophy of the nerve trunks. Quantitative criteria considered more than 20% giant ganglia in the submucosa, with more than eight neurons each on 25 ganglia, and children aged over 1 year. Distal colon surgical specimens from 29 patients, aged 0-16 years, diagnosed with intestinal neuronal dysplasia type B were retrospectively analyzed using sections processed for conventional histology (H&E) and calretinin immunohistochemistry. Hyperplasia of the submucosal nerve plexi with hyperganglionosis and hypertrophy of the nerve trunks was observed in all cases. Ganglia with small, immature neurons were detected in the majority of cases. Quantitative analysis confirmed hyperganglionosis (mean number=10.7 neurons per ganglion) and hypertrophy of the nerve trunks (median=44.6 μm thickness). Neurons showed immunostaining for calretinin, but neuron counts in calretinin-stained sections were lower compared with H&E (P<0.01). No significant differences were verified between children aged under and over 1 year regarding hyperganglionosis (P=0.79), neuron counts (P=0.36), and immature ganglia (P=0.66). Only one patient met the numerical criteria proposed by Meier-Ruge et al in 2004 and 2006. In conclusion, the numerical criteria showed limited applicability when transposed to conventional histopathology. Children aged over 1 year presented very similar histological features of neuronal immaturity to younger children, questioning the need for an age criterion when diagnosing intestinal neuronal dysplasia type B.

The utility of the hematoxylin and eosin staining in patients with suspected Hirschsprung disease

Background

While immunohistochemistry (IHC) methods have been widely conducted for the diagnosis of Hirschsprung disease (HSCR) in developed countries, there are very few studies on their use in developing countries where hematoxylin and eosin (HE) staining is a key element of the diagnosis of HSCR. We aimed to determine the accuracy of HE staining in the diagnosis of HSCR using S100 IHC as the reference standard in Indonesia.

Methods

All histopathology performed for the suspicion of HSCR patients from January 2013 to August 2015 in Dr. Sardjito Hospital, Yogyakarta, Indonesia, were retrospectively reviewed.

Results

Our study included 23 HSCR patients: 9 males and 14 females. The HE staining revealed 14 negative (absence of ganglion cells) cases (61%) and 9 positive (presence of ganglion cells) cases (39%). In S100 IHC, out of the 9 positive cases by HE staining, 6 (67%) were confirmed for having ganglion cells; and out of the 14 negative cases by HE staining, 12 (86%) were reported negative and 2 (14%) were positive by S100 IHC staining. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy rates of the HE staining were 80% (95% CI: 0.51–0.95), 75% (95% CI: 0.36–0.96), 85.7% (95% CI: 0.56–0.98), 66.7% (95% CI: 0.31–0.91), and 78.3% (95% CI: 0.58–0.90), respectively.

Conclusions

Our study showed that HE staining has relatively moderate accuracy for the diagnosis of HSCR. The use of HE staining is still recommended for the diagnosis of HSCR given the limitation of resource allocation for more expensive IHC technologies in developing countries.

Review of Current Applications of Immunohistochemistry in Pediatric Nonneoplastic Gastrointestinal, Hepatobiliary, and Pancreatic Lesions

Immunohistochemical (IHC) stains are widely used by pathologists for a variety of considerations in the diagnostic workup of pediatric nonneoplastic lesions in gastrointestinal (GI), hepatic, biliary, and pancreatic lesions. The pathologic changes cover a wide range and types of presentations, including inflammatory (bacterial and viral), metaplastic, posttransplant lymphoproliferative, autoimmune, metabolic, degenerative, developmental, and genetic conditions, among others. The everyday practical value of IHC stains covers primary identification, confirmation, differential, and/or exclusionary roles in the hands and eyes and minds of the practitioners. This article is intended to review and discuss the currently available IHC stains for a variety of pediatric GI, hepatobiliary, and pancreatic lesions as encountered in the day-to-day practice of pathologists and clinicians. It reflects the most recent methods and types of IHC stains with the stated aim of helping to provide a quick reference for diagnostic considerations and thereby facilitate the workup of a broad range of GI and related conditions in a pediatric population. The tables provide a handy reference on a wide range of IHC stains for commonly encountered lesions covering a variety of pediatric GI, hepatobiliary, and pancreatic conditions that are amenable to light microscopic diagnostic interpretation.

Diagnostic roles of calretinin in hirschsprung disease: A comparison to neuron-specific enolase

BACKGROUND/AIM

Diagnosis of Hirschsprung's disease (HD) can be hard and requires good experience, principally for pathologists who infrequently encounter the disease. However, diagnosis is not always possible with hematoxylin and eosin (H and E) because staining has limitations in the identification of immature ganglion cells in neonates and the submucosal area.

AIM

To assess the diagnostic role of calretinin immunostaining in HD in comparison to neuron-specific enolase.

PATIENTS AND METHODS

Formalin-fixed paraffin tissue blocks of full-thickness distal colonic and rectal biopsies for 48 patients who clinically presented with symptoms suspicious for HD were collected for the period from December 2012 to January 2016. All biopsies were already studied by routine H and E histopathological examination for the presence or absence of ganglion cells. Further confirmation of ganglion cells and nerve fibers was performed by immunohistochemical study for neuron-specific enolase and calretinin, respectively, in a private pathology laboratory.

RESULTS

According to the histopathological assessment, cases with absent ganglionic cells were considered to be HD, which comprised 40 cases out of the total 48 cases. The mean age for HD cases was 19.43 months. The male-to-female ratio in HD cases was 2.34:1. All HD cases showed negative expression of calretinin in small nerve fibers of the lamina propria, musularis mucosae, and submucosa, and negative expression of neuron-specific enolase in ganglionic cells. The sensitivity, specificity, positive predictive value, and negative predictive values for both the markers in the confirmation of diagnosis of HD were all 100%.

CONCLUSION

Calretinin immunostaining, similar to that of neuron-specific enolase, is a highly sensitive and specific diagnostic aid to histopathological examination in suspected HD.

Diagnostic value of rectal suction biopsies using calretinin immunohistochemical staining in Hirschsprung's disease

BACKGROUND

The study investigates the diagnostic value of calretinin immunohistochemical staining (CIS) on rectal suction biopsies (RSB) in Hirschsprung's disease (HD).

METHODS

A prospective study was conducted at Children's Hospital 2 in Ho Chi Minh City, Vietnam, from January through December 2015. Patients suspected of HD during this period underwent RSB and were followed in order to assess the accuracy of the diagnostic test with CIS compared with conventional histology (H&E).

RESULTS

A total of 188 children with RSB were investigated. Median age was 7.1 (range 0.2-159) months with 65.4% boys. HD was confirmed in 80 (42.6%) children. There were 1 false positive and no false-negative cases. The sensitivity and specificity were 100% (80/80) and 99.1% (107/108) for CIS and 100% and 85.2% for H&E, respectively. Cohen's kappa coefficient was 0.9891 with a diagnostic accuracy of 99.5% for CIS, compared with 0.8303 and 91.5% for H&E, respectively. There were no serious complications related to the RSB.

CONCLUSION

RSB with CIS is a useful diagnostic method for HD, with easy interpretation and no need for cryostat. CIS has a high diagnostic accuracy and should be considered as the primary method for the diagnosis of HD by RSB.

LEVEL OF EVIDENCE

Diagnostic Studies - Level I.

Bowel dysfunction following pullthrough surgery is associated with an overabundance of nitrergic neurons in Hirschsprung disease

PURPOSE

Recent evidence suggests that patients with Hirschsprung disease (HD) have abnormal neurotransmitter expression in the ganglionated proximal colon. These alterations may cause persistent bowel dysfunction even after pullthrough surgery. We sought to quantify the proportion of nitrergic neurons in the ganglionic colon of HD patients and relate these findings to functional outcome.

METHODS

The proximal resection margin from 17 patients with colonic HD who underwent a pullthrough procedure and colorectal tissue from 4 age-matched controls were immunohistochemically examined to quantify the proportion of nitrergic neurons. The incidence of constipation, incontinence, and enterocolitis in HD patients was assessed retrospectively and correlated with the proportion of nitric oxide synthase (NOS) expressing neurons. Neuronal subtypes in the ganglionic colon of the Edrnb^-/- mouse model of HD were also studied.

RESULTS

Mice with HD had a significantly higher proportion of NOS+ neurons in ganglionic colon than normal littermates (32.0±5.6% vs. 19.8±1.2%, p<0.01). Patients with HD also had significantly more NOS+ neurons than controls (18.4±4.6% vs. 13.1±1.9%, p<0.01). Patients who experienced constipation or enterocolitis postoperatively tended toward a higher proportion of NOS+ neurons (21.4±3.9% vs. 17.1±4.1%, p=0.06). Furthermore, patients with a proportion of NOS+ neurons above the median of all HD patients (18.3%) were significantly more likely to have constipation than those below the median (75% vs. 14%, p<0.05).

CONCLUSION

An overabundance of nitrergic neurons in the proximal resection margin is associated with HD and may predict bowel dysfunction following pullthrough surgery.

Effectiveness of calretinin and role of age in the diagnosis of Hirschsprung disease

OBJECTIVE

Gold standard in Hirschsprung disease (HD) diagnosis is rectal suction biopsy (RSB) with hematoxylin and eosin and acetylcholinesterase (ACE) stainings. Sensitivity is 83-93 % and specificity is between 95 and 99 %. The rate of non-conclusive results (NC) due to inadequate samples or variability in the interpretation is about 11-37.8 %. Interpretation is still difficult in neonates. Calretinin (C) is a calcium-binding protein, expressed in the nervous system. It has been introduced as a marker to improve the diagnosis accuracy in HD. We compare sensitivity, specificity between ACE and ACE + C and investigate whether the introduction of C could reduce the rate of inconclusive results. We also tried to define the most adequate age to obtain accurate results from RSB.

METHODS

Data from patients undergoing rectal suction biopsies from 2005 to 2014 was analyzed. Until 2010 we used ACE; since 2011 we used ACE + C. The ROC curve analysis of the NC results regarding the age, showed an optimal cut-off point at 1.5 months (m). It divides the sample into two groups which we compared.

RESULTS

We analyzed 91 patients. Results of the RSB: 40 HD (44 %), 34 no Hirschsprung (37.4 %) and 17 NC (18.7 %). Sensitivity = 97.5 %, specificity = 97.1 %, not including the NC (1 false positive, 1 false negative). Results depending on the staining: ACE (n = 58) (%) ACE + C (n = 33) (%) p Sensitivity 96 100 1 Specificity 94.7 100 1 NC 24.1 9.1 0.077 Results depending on the age: <1.5 m (n = 27) (%) >1.5 m (n = 64) (%) p Sensitivity 92.3 100 0.325 Specificity 100 96.8 1 NC 40.7 9.4 0.001 CONCLUSION: Calretinin decreases the rate of inconclusive results, but not significantly. The percentage of inconclusive results decreases in patients olders than 1.5 m. Further studies are necessary to determine if this technique is useful to improve RSB results in infants younger than 1.5 months.

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.

Calretinin, S100 and protein gene product 9.5 immunostaining of rectal suction biopsies in the diagnosis of Hirschsprung' disease

Evaluation of rectal suction biopsies for the ganglion cells and neural hypertrophy is the basic modality for the diagnosis of Hirschsprung's disease (HD). However, the traditional hematoxylin and eosin staining coupled with acetylcholinesterase histochemistry remain challenging, especially in newborns. Thus we conducted a prospective study to evaluate the usefulness of calretinin combined with S100 and protein gene product 9.5 (PGP9.5) immunostaining of rectal suction biopsies for the diagnosis of HD. A total of 195 patients were enrolled in our study. Of the 195 patients 69% had ganglion cells on the initial diagnostic protocol. Sixty cases were devoid of ganglion cells, and of these, 90% and 91% showed submucosal neural hypertrophy on S-100 staining and PGP9.5 staining, respectively. Eighty-one patients underwent a colonic resection, and of these, 59 had confirmed aganglionic segment, the other 22 patients were diagnosed as intestinal neuronal dysplasia type B (n=13) and isolated hypoganglionosis (n=9). Of the rest 114 patients, 51 cases underwent a full-thickness biopsy, and HD was excluded; sixty-three patients were thoroughly followed-up with no evidence of HD. We encountered two false-negatives and they were proved to be short segment HD after the surgery. The sensitivity and specificity rates of our diagnostic protocol was 96.49% (95% CI, 0.88-0.99) and 100% (95% CI, 0.97-1.00), respectively, excluding 5 patients with inconclusive results. Our findings demonstrated that calretinin coupled with S100 and PGP9.5 immunostaining on suction rectal biopsies is sensitive and specific for diagnosing HD.

Rectal biopsies for Hirschsprung disease: Patient characteristics by diagnosis and attending specialty

PURPOSE

Hirschsprung disease (HD) is diagnosed with rectal biopsy. At our institution two services perform these biopsies: pediatric surgery and gastroenterology. Our objective was to review our institutional experience with rectal biopsies to diagnose HD and compare patients and outcomes between the two services.

METHODS

We reviewed all children undergoing a rectal biopsy for the evaluation of HD at our institution over a 10-year period. Comparisons were made using multiple logistic regression models.

RESULTS

We identified 518 children who underwent rectal biopsy for evaluation of HD; 451/518 (87%) were adequate and 56/518 (11%) were positive for HD. A positive biopsy was more likely with delayed passage of meconium (p<0.001), obstructive symptoms (p<0.001), trisomy 21 (p<0.001), full-term gestation (p=0.03), and male gender (p=0.02). Pediatric surgeons biopsied younger patients with more classic symptoms for HD compared to gastroenterologists. Pediatric surgeons were more likely to take adequate (OR 6.0, 95% CI 2.9-12.4, p<0.001) and positive biopsies (OR 6.7 95% CI 2.1-21.2, p=0.001) compared to gastroenterologists.

CONCLUSION

Infants with classic symptoms can reliably be diagnosed with HD by a pediatric surgeon. The work up for HD in older children with constipation should be a collaborative effort between pediatric surgery and gastroenterology.

The zebrafish mutant lessen: an experimental model for congenital enteric neuropathies

BACKGROUND

Congenital enteric neuropathies of the distal intestine (CEN) are characterized by the partial or complete absence of enteric neurons. Over the last decade, zebrafish has emerged as a leading model organism in experimental research. Our aim was to demonstrate that the mutant zebrafish, lessen, expressing CEN characteristics, is an equally valuable animal model alongside mammalian models for CEN, by studying its enteric phenotype.

METHODS

The effect of the lessen mutation on the development of the enteric nervous system (ENS), interstitial cells of Cajal (ICC), and intestinal motility in each intestinal region of mutant and wild-type (wt) zebrafish embryos at 3-6 dpf, was analyzed by immunofluorescent detection of neurochemical markers and motility assays.

KEY RESULTS

Development of intestinal motility in the mutant was delayed and the majority of the observed contractions were disturbed. A significant disturbance in ENS development resulted in a distal intestine that was almost free of neuronal elements, in reduced neuronal density in the proximal and mid-intestine, and in a defect in the expression of neurochemical markers. Furthermore, markedly disturbed development of ICC gave rise to a less dense network of ICC.

CONCLUSIONS & INFERENCES

The observed alterations in intestinal motility, intrinsic innervation and ICC network of the mutant in comparison with the wt zebrafish, are similar to those seen in the oligo- and aganglionic regions of the intestine of CEN patients. It is concluded that the zebrafish mutant lessen is an appropriate animal model to investigate CEN.

Hirschsprung Disease Diagnosis: Calretinin Marker Role in Determining the Presence or Absence of Ganglion Cells

BACKGROUND

Hirschsprung disease is a complex genetic disorder of the enteric nervous system (ENS), often called congenital aganglionic megacolon and characterized by the absence of enteric neurons along a variable length of the intestine. The definitive diagnosis of Hirschsprung disease relies on histologic and/or histochemical staining of sections from suction rectal biopsies. Calretinin immunohistochemistry (IHC) may be a useful in its diagnosis. This study aimed to proof the usefulness of immunohistochemical staining for calretinin in rule out of Hirschsprung disease.

METHODS

Paraffin blocks and slides were retrieved from the pathology archives of Ali Asghar Hospital, Tehran, Iran from 2007 to 2011 with pathology report based on the presence (14 patients) or absence (70 patients) of ganglion cells and transitional zone anatomical region (10 patients). Slides were stained with hematoxylin and eosin method to confirm the initial diagnosis was verification again. After preparing the slides, they were stained by IHC for calretinin. Then, the results were analyzed using SPSS software.

RESULTS

In most patients, IHC for calretinin provided highly compatible results with hematoxylin-eosin findings in diagnosis of Hirschsprung disease. The values of specificity and accuracy between calretinin and standard histology (H&E) compared by the Fisher exact test declared calretinin presented significantly higher specificity and accuracy values than H&E staining (P <0.0001).

CONCLUSION

Calretinin IHC overcomes most of the difficulties encountered using the histology hematoxylin-eosin. Then, IHC for calretinin is a good ancillary method used by pathologists in diagnosis of Hirschsprung disease.

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.

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.

Hirschsprung's Disease in Neonates with Special Reference to Calretinin Immunohistochemistry

BACKGROUND

Hirschsprung's disease is a classic example of a complex genetic disease, characterized by the lack of enteric ganglia in the submucosal and myenteric plexuses, along variable portions of the distal gut. The diagnosis of Hirschsprung's disease is based on a combination of clinical features, radiological appearance of the bowel and histological features in Haematoxylin & Eosin stained sections of intestinal biopsies. Calretinin Immunohistochemistry is emerging to be one of the newer methods.

AIMS AND OBJECTIVES

This study was undertaken to ascertain 1) clinical profile; 2) mode of presentation; 3) to evaluate the role of Calretinin immunostain in the diagnosis of Hirschsprung's Disease.

MATERIALS AND METHODS

This prospective and observational study was conducted in the Department of Pathology IPGME&R from July 2013 to September 2014. Eighty nine patients, clinically and radiologically diagnosed with Hirschsprung's disease underwent surgery and were included in the study. The data of every patient including age, sex and presenting symptoms were recorded. Eventually, histopathological examination & immunohistochemistry were done.

RESULTS

Total number of cases studied was 89 which aged between 0 days to 28 days. Overall sensitivity in our study to diagnose presence or absence of ganglion cells by calretinin immunohistochemistry was 100% and the specificity is 97.44% with positive and negative predictive value of 84.62 % and 100 % respectively.

CONCLUSION

Calretinin immunohistochemistry holds several advantages, and it's simple and not doubtful; and it is either positive or negative.

Isolation of Enteric Nervous System Progenitor Cells from the Aganglionic Gut of Patients with Hirschsprung's Disease

Enteric nervous system progenitor cells isolated from postnatal human gut and cultured as neurospheres can then be transplanted into aganglionic gut to restore normal patterns of contractility. These progenitor cells may be of future use to treat patients with Hirschprung’s disease, a congenital condition characterized by hindgut dysmotility due to the lack of enteric nervous system ganglia. Here we demonstrate that progenitor cells can also be isolated from aganglionic gut removed during corrective surgery for Hirschsprung’s disease. Although the enteric nervous system marker calretinin is not expressed in the aganglionic gut region, de novo expression is initiated in cultured neurosphere cells isolated from aganglionic Hirschsprung bowel. Furthermore, expression of the neural markers NOS, VIP and GFAP also increased during culture of aganglionic gut neurospheres which we show can be transplantation into cultured embryonic mouse gut explants to restore a normal frequency of contractility. To determine the origin of the progenitor cells in aganglionic region, we used fluorescence-activated cell sorting to demonstrate that only p75-positive neural crest-derived cells present in the thickened nerve trunks characteristic of the aganglionic region of Hirschsprung gut gave rise to neurons in culture. The derivation of enteric nervous system progenitors in the aganglionic gut region of Hirschprung’s patients not only means that this tissue is a potential source of cells for future autologous transplantation, but it also raises the possibility of inducing the differentiation of these endogenous cells in situ to compensate for the aganglionosis.

Laboratory procedures update on Hirschsprung disease

OBJECTIVES

The detection of ganglion cells in rectal biopsies of infants or toddlers with severe constipation is routinely performed by pediatric pathologists in many institutions. Hirschsprung disease (HD) is defined by the lack of ganglion cells (aganglionosis). The early recognition and the prompt implementation of surgical procedures obviously protect infants affected with HD from potential life-threatening conditions, including enterocolitis and debilitating constipation. Image-based and non-image-based clinical techniques and some laboratory tests have been reevaluated along the years, but often fragmentarily. Immunohistochemical markers have been increasingly used in pathology laboratories to detect ganglion cells and nerve fibers. Recently, calretinin, a vitamin D-dependent calcium-binding protein with expression in ganglion cells and nerves, has been described as an adjunctive or primary diagnostic test in HD. The aim of the present study was to systematically summarize and update laboratory procedures targeting ganglion cells in rectal biopsies.

METHODS

Procedures and tests have been reviewed and values of specificity and sensitivity have been calculated according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Contrast enema has the lowest sensitivity and specificity of all of the 3-index investigations under the lens: contrast enema, anorectal manometry, and biopsy with histology. The latter procedure seems to have the highest sensitivity and specificity. Acetylcholinesterase staining on fresh-frozen material has been found to have slightly higher rates of sensitivity and specificity when compared with hematoxylin and eosin only. Calretinin staining may be supportive for the diagnosis, although some cases with false-positivity may be of some concern.

CONCLUSIONS

Hematoxylin and eosin with or without acetylcholinesterase remains the criterion standard according to our PRISMA-based data. In our opinion, the number of false-positive results with potential overtreatment may limit the increasing advocacy for calretinin staining. Both the "primum non nocere" dictum and the "loss aversion heuristic" need to be satisfied harmoniously by preventing harm from unnecessary surgery.

Evaluation of Calretinin as a New Marker in the Diagnosis of Hirschsprung Disease

Background:

Hirschsprung’s disease (HD) is a congenital intestinal motility disorder with absence of ganglion cells in the colonic wall. Diagnosis of the disease is mainly based on the identification of the lack of ganglion cells in the pathology sections of the colon which is very difficult and time consuming and also needs several serial cut sections. There are many proposed markers in this field in the literature but none of them has been satisfactory. Calretinin immunohistochemistry (IHC) has been introduced as a new diagnostic marker to overcome the problems in diagnosis of this disease about 5 years ago. However there are few studies regarding the benefits and pitfalls of this marker.

Objectives:

The aim of this study is to determine the diagnostic value of calretinin IHC in detecting aganglionosis (HD).

Patients and Methods:

27 HD patients and 28 non-Hirschsprung’s disease (NHD) patients were collected in a prospective study and calretinin IHC was performed on 31 aganglionic and 51 normoganglionic full wall thickness sections of colectomies (some of the cases had more than 1 section). The IHC slides were evaluated by two pathologists and the diagnostic value was calculated in comparison with gold standard which is the presence or absence of ganglion cells in serial Hematoxylin and Eosin (HE) stained sections of the colectomies.

Results:

There was great concordance between the final diagnosis of both pathologists and gold standard (k > 0.9). Calretinin immunostaining showed 100% specificity and positive predictive value and more than 90% sensitivity and negative predictive value. High agreement was present between the two pathologists (k > 0.9).

Conclusions:

Calretinin IHC is a very convenient, useful and valuable method to demonstrate aganglionosis in HD patients. Loss of calretinin immunostaining in lamina propria and submucosa is characteristic of HD.

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.

Presence of intramucosal neuroglial cells in normal and aganglionic human colon

The enteric nervous system (ENS) is composed of neural crest-derived neurons (also known as ganglion cells) the cell bodies of which are located in the submucosal and myenteric plexuses of the intestinal wall. Intramucosal ganglion cells are known to exist but are rare and often considered ectopic. Also derived from the neural crest are enteric glial cells that populate the ganglia and the associated nerves, as well as the lamina propria of the intestinal mucosa. In Hirschsprung disease (HSCR), ganglion cells are absent from the distal gut because of a failure of neural crest-derived progenitor cells to complete their rostrocaudal migration during embryogenesis. The fate of intramucosal glial cells in human HSCR is essentially unknown. We demonstrate a network of intramucosal cells that exhibit dendritic morphology typical of neurons and glial cells. These dendritic cells are present throughout the human gut and express Tuj1, S100, glial fibrillary acidic protein, CD56, synaptophysin, and calretinin, consistent with mixed or overlapping neuroglial differentiation. The cells are present in aganglionic colon from patients with HSCR, but with an altered immunophenotype. Coexpression of Tuj1 and HNK1 in this cell population supports a neural crest origin. These findings extend and challenge the current understanding of ENS microanatomy and suggest the existence of an intramucosal population of neural crest-derived cells, present in HSCR, with overlapping immunophenotype of neurons and glia. Intramucosal neuroglial cells have not been previously recognized, and their presence in HSCR poses new questions about ENS development and the pathobiology of HSCR that merit further investigation.

Diagnosis of Hirschsprung's disease with particular emphasis on histopathology. A systematic review of current literature

Hirschsprung's disease (HD) is a disorder that involves several medical specialties such as paediatric gastroenterology, paediatric surgery, and pathology. Hirschsprung's disease is a congenital bowel innervation disorder characterised by the absence of ganglion cells in myenteric (Auerbach) and submucosal (Meissner) plexus in the distal colon in its classical form. Rapid and accurate diagnosis of HD is a key element in further treatment patterns. The efficiency of different diagnostic methods used in HD patients may vary. Using one limited diagnostic procedure can lead to as much as a few per cent of overlooked cases. In recent years, rectal biopsy was recognised as an important diagnostic tool that allows for a definitive HD diagnosis with an accuracy of 95% of cases. A correct diagnosis depends on the localisation of the biopsied sample, its representativeness, the number of specimens, and proper interpretation of microscopic studies supported by histochemical and immunohistochemical methods. When several methods are used and all diagnostic criteria are used, the diagnostic sensitivity can almost eliminate cases of undiagnosed patients.

A variant pattern of calretinin immunohistochemistry on rectal suction-biopsies is fully specific of short-segment Hirschsprung's disease

BACKGROUND/PURPOSE

Calretinin immunohistochemistry is now widely used to diagnose Hirschsprung's disease (HD), since loss of calretinin expression within the mucosa and muscularis mucosae of rectal suction-biopsy is pathognomonic of HD. However, a stippled staining may be observed within hypertrophic nerves in the submucosae in some HD patients. The aim of the study was to test the hypothesis that such findings may announce the beginning of the transitional zone.

METHODS

We retrieved 44 consecutive patients (10 girls and 34 boys; median age 6.5 days), diagnosed with aganglionosis on rectal suction biopsies, followed by surgery. According to calretinin immunohistochemistry performed on all paraffin-embedded rectal biopsies, we defined two HD groups: P- showing an absence of any staining within mucosa, muscularis mucosae and submucosa et P+ showing an absence of staining within the mucosa and muscularis mucosae, but a positivity of some submucosal hypertrophic nerves. These data were correlated to the length of total pathological segment (aganglionic and transitional zones) obtained from the original surgery reports.

RESULTS

18/44 patients (40.9 %) belonged to the P+ group and 26/44 (59 %) patients were within the P- group. In the P+ group, the maximal length of the aganglionic zone was 9 cm [mean 4 (1-9)] and the total pathological zone never exceeded 14 cm [mean 8 (3.8-14)]. In the P- group, the maximal length of aganglionic zone was 55.5 cm [mean 11.3 (2.5; 55.5)] and the total pathological zone extended to 59.5 cm [mean 17.75 (4.5; 59.5)]. Aganglionic segment was significantly shorter in the P+ group (p < 0.0001).

CONCLUSION

Staining of some hypertrophic nerves in the submucosa in suction rectal biopsy of HD patients using calretinin immunohistochemistry is only encountered in short-segment aganglionosis with a pathological zone always restricted to rectal and sigmoid colon. This information could be crucial for the surgeons in the decision to choose a transanal procedure.

Expression profiles of HA117 and its neighboring gene DPF3 in different colon segments of Hirschsprung's disease

Hirschsprung's disease (HSCR) is characterized by the absence of enteric ganglion cells along variable regions of the colon. Established theory demonstrates that HSCR is the consequence caused by the abnormal arrest of the migration and differentiation of neural crest-derived stem cells (NCSCs). And retinoid signaling was considered to be involved. We speculated that, HA117, a retinoid-related transcript of a long noncoding RNA (LncRNA), may be involved in the genesis of HSCR. In current research, colon specimens were collected from 25 HSCR patients and grouped into 3 segments: proximal anastomosis, dilated segment and stenotic segment. Real-Time PCR was used to analyze the expression profiles of HA117 and its neighboring gene DPF3 in different colon segments. Fluorescence in situ hybridization (FISH) was employed to detect the distribution of HA117 in the gut wall. Immunohistochemistry was performed to analyze the protein expression of DPF3 in different colon segments. HA117 expression in stenotic segment was higher compared to proximal anastomosis and dilated segment (p < 0.05). Whereas DPF3b mRNA was lower in stenotic segment than that in two other segments (p < 0.05). FISH detected HA117 was distributed in mucosa and muscle layer, mainly present in stenotic segment. Immunohistochemical staining showed that intensive DPF3 staining occurred in proximal anastomosis and the positive staining was hardly observed in stenotic segment. The results suggested that HA117 may be a factor exerting an anti-differentiation or or anti-maturation role in the genesis of HSCR. This gave us a novel cue for better understanding the etiology of HSCR.

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, β-tubulin immunohistochemistry, and submucosal nerve trunks morphology in Hirschsprung disease: possible applications in clinical practice

OBJECTIVES

The aim of this study was to investigate calretinin and β-tubulin immunohistochemical expression together with submucosal nerve trunks morphology in differently innervated segments of Hirschsprung disease (HD) and total colonic aganglionosis (TCA).

METHODS

A total of 25 cases (22 HD, 3 TCA) and 18 controls were processed for calretinin and β-tubulin immunohistochemistry. Sections representative of distal aganglionic, transition, and proximal ganglionic segments were evaluated by a visual grading score; β-tubulin was evaluated also by image analysis. Submucosal nerve trunks hypertrophy and hyperplasia were measured by citomorphology. The length of proximal segment was correlated to postoperative bowel function.

RESULTS

Controls showed intense calretinin and β-tubulin staining. In HD and TCA, calretinin staining was related to the presence of ganglion cells: negative in distal, faint in transition, intense in proximal segment. β-Tubulin staining was weak in all of the segments of HD and negative in TCA. Hypertrophic and hyperplastic nerve trunks characterized aganglionic segment, and progressively decreasing nerve size was observed in transition and ganglionic segments. Transient postoperative constipation, soiling, or enterocolitis was present in 59% of patients with HD without clear relation to proximal segment length or presence of hypertrophic nerve trunks.

CONCLUSIONS

Calretinin is a reliable marker of the presence of ganglion cells, and, together with nerve hypertrophy, it helps to identify the transition zone. Length and nerve size of proximal segment in resected specimen did not affect the postsurgical intestinal function. Reduced β-tubulin expression along the entire colonic tract, included proximal ganglionic segments, may represent a potential impairing factor for the enteric neural transmission.