Diagnostic Algorithm in Hirschsprung's Disease: Focus on Immunohistochemistry Markers

Full-Thickness Rectal Biopsy in Children Suspected of Having Hirschsprung's Disease: The Inconclusive Biopsy

The diagnosis of Hirschsprung's disease relies on histologically proven aganglionosis and nerve trunk hypertrophy in rectal biopsies. Although the frequency of inconclusive biopsies is relatively low, it is a relevant clinical problem. The aim of the present study was to investigate whether a re-evaluation of archived full-thickness biopsies (FTBs) stained with hematoxylin and eosin (HE), together with immune histochemical (IHC) staining, would be diagnostic in biopsies otherwise deemed inconclusive at initial examination with HE only. A total of 34 inconclusive biopsies in 31 patients were identified. From each tissue block, three slices were cut and stained with HE, S100 and calretinin. A blinded pathologist examined the tissue samples. At re-evaluation, one patient was found positive for HD and 11 negative for HD with both HE and IHC staining, respectively. In all 12 cases, the result was confirmed by the final diagnosis at a 5-year follow-up. The rest of the cases were deemed inconclusive. A re-evaluation of the remaining tissue from the biobank might have saved one third of the children from a re-biopsy. The value of adding IHC to conventional HE staining is dubious.

Ultra-High Frequency Ultrasound Imaging of Bowel Wall in Hirschsprung's Disease-Correlation and Agreement Analyses of Histoanatomy

Hirschsprung's disease (HD) is characterized by aganglionosis in the bowel wall, requiring resection. Ultra-high frequency ultrasound (UHFUS) imaging of the bowel wall has been suggested to be an instantaneous method of deciding resection length. The aim of this study was to validate UHFUS imaging of the bowel wall in children with HD by exploring the correlation and systematic differences between UHFUS and histopathology. Resected fresh bowel specimens of children 0-1 years old, operated on for rectosigmoid aganglionosis at a national HD center 2018-2021, were examined ex vivo with UHFUS center frequency 50 MHz. Aganglionosis and ganglionosis were confirmed by histopathological staining and immunohistochemistry. Histoanatomical layers of bowel wall in histopathological and UHFUS images, respectively, were outlined using MATLAB programs. Both histopathological and UHFUS images were available for 19 aganglionic and 18 ganglionic specimens. The thickness of muscularis interna correlated positively between histopathology and UHFUS in both aganglionosis (R = 0.651, p = 0.003) and ganglionosis (R = 0.534, p = 0.023). The muscularis interna was systematically thicker in histopathology than in UHFUS images in both aganglionosis (0.499 vs. 0.309 mm; p < 0.001) and ganglionosis (0.644 versus 0.556 mm; p = 0.003). Significant correlations and systematic differences between histopathological and UHFUS images support the hypothesis that UHFUS reproduces the histoanatomy of the bowel wall in HD accurately.

Histopathological dimensions differ between aganglionic and ganglionic bowel wall in children with Hirschsprung's disease

BACKGROUND

In the validation of new imaging technology for children with Hirschsprung's disease (HSCR), basic anatomical parameters of the bowel wall must be established specifically for this patient group.

AIM

To explore differences in histoanatomical layers of bowel wall, comparing ganglionic and aganglionic bowel walls, and to examine if the bowel wall thickness is linked to patient weight.

METHODS

This was an observational study of bowel specimens from children weighing 0-10 kg, operated on consecutively during 2018-2020. Ganglionic and aganglionic bowel walls were measured in digitalized microscopy images from 10 sites per trans-sectional specimen and compared regarding the thickness of their histoanatomical layers.

RESULTS

Bowel walls were measured in 21 children. Full bowel wall thickness did not differ between aganglionic and ganglionic bowel (2.20 vs 2.04; p = 0.802) while weight at surgery correlated positively with both ganglionic and aganglionic bowel wall thickness (r = 0.688 and 0.849, respectively), and age at surgery with ganglionic bowel wall thickness (r = 0.517). In aganglionic segments, the muscularis externa layer was thicker compared to that in ganglionosis (0.45 vs 0.31 mm, p = 0.012) whereas the muscularis interna was thinner (0.45 vs 0.62 mm, p < 0.001). A diagnostic index was identified whereby a lower ratio of muscularis interna/externa thickness followed by a thinner muscularis interna differed between aganglionic and ganglionic bowel in all specimens.

CONCLUSION

Thicknesses of the bowel wall's muscle layers differ between aganglionic and ganglionic bowel walls in children with HSCR. These findings support a diagnostic index that could be validated for transfer to instant diagnostic imaging techniques.

LEVEL OF EVIDENCE

Diagnostic: 3.

Role of the Intermediate Filament Protein Peripherin in Health and Disease

Intermediate filaments are the most heterogeneous class among cytoskeletal elements. While some of them have been well-characterized, little is known about peripherin. Peripherin is a class III intermediate filament protein with a specific expression in the peripheral nervous system. Epigenetic modifications are involved in this cell-type-specific expression. Peripherin has important roles in neurite outgrowth and stability, axonal transport, and axonal myelination. Moreover, peripherin interacts with proteins involved in vesicular trafficking, signal transduction, DNA/RNA processing, protein folding, and mitochondrial metabolism, suggesting a role in all these processes. This review collects information regarding peripherin gene regulation, post-translational modifications, and functions and its involvement in the onset of a number of diseases.

Opportunities for novel diagnostic and cell-based therapies for Hirschsprung disease

Despite significant progress in our understanding of the etiology and pathophysiology of Hirschsprung disease (HSCR), early and accurate diagnosis and operative management can be challenging. Moreover, long-term morbidity following surgery, including fecal incontinence, constipation, and Hirschsprung-associated enterocolitis (HAEC), remains problematic. Recent advances applying state-of-the art imaging for visualization of the enteric nervous system and utilizing neuronal stem cells to replace the missing enteric neurons and glial cells offer the possibility of a promising new future for patients with HSCR. In this review, we summarize recent research advances that may one day offer novel approaches for the diagnosis and management of this disease.

Challenges in the diagnosis of intestinal neuronal dysplasia type B: A look beyond the number of ganglion cells

Intestinal neuronal dysplasia type B (IND-B) is a controversial condition among gastrointestinal neuromuscular disorders. Constipation is its most common clinical manifestation in patients. Despite intense scientific research, there are still knowledge gaps regarding the diagnostic criteria for IND-B in the histopathological analysis of rectal biopsies. The guidelines published in the past three decades have directed diagnostic criteria for quantifying the number of ganglion cells in the nervous plexus of the enteric nervous system. However, it is very complex to distinguish numerically what is pathological from what is normal, mainly because of the difficulty in determining a reliable control group composed of healthy children without intestinal symptoms. Thus, a series of immunohistochemical markers have been proposed to assist in the histopathological analysis of the enteric nervous system. Several of these markers facilitate the identification of other structures of the enteric nervous system, in addition to ganglion cells. These structures may be related to the etiopathogenesis of IND-B and represent new possibilities for the histopathological diagnosis of this disease, providing a view beyond the number of ganglion cells. This review critically discusses the aspects related to the disease definitions and diagnostic criteria of this organic cause of constipation.

Clinical Spectrum and Outcomes of Neonatal Necrotizing Enterocolitis

BACKGROUND/AIM

The objective of the study was analysis of risk factors associated with outcome of necrotizing enterocolitis (NEC) in infants in a single-center study.

PATIENTS AND METHODS

All consecutive infants hospitalized for NEC over a period of 6 years were retrospectively analyzed for clinical course, infections, treatment and outcome.

RESULTS

Out of 76 patients, surgical management was applied in 56 (53 exploratory laparotomy, three initial peritoneal drain placement) and in 20 there was only a conservative approach. Segmental intestinal resection was performed in 41 patients. Survival from NEC in our cohort was 79%. We found that independent adverse risk factors of outcome of newborns and infants with NEC were gut perforation, infection, abdominal wall erythema, and development of acute kidney injury.

CONCLUSION

We underline the value of both surgical and conservative approach with careful management in this cohort of patients.