Segmental aganglionosis (zonal aganglionosis or "skip" lesions) in Hirschsprungs disease: a report of 2 unusual cases

Skip Segment Hirschsprung Disease Managed by Pull-Through of the Right Colon

Hirschsprung disease is the most common neurocristopathy in children, resulting in the congenital loss of enteric ganglia. Rare reports of skip lesions have previously been reported in the literature. We present a case of skip lesions known prior to surgery and managed by pull-through of the right colon that allowed the preservation of the colon.

Case report of a skip segment Hirschsprung's disease: A real phenomenon

INTRODUCTION AND IMPORTANCE

Hirschsprung's disease is a congenital anomaly that results from an incomplete craniocaudal migration and maturation of intestinal ganglion progenitor cells leading to distal intestinal aganglionosis. Skip segment Hirschsprung's disease is an extremely rare phenomenon. We report a case involving only the small bowel with confirmed colonic ganglionosis.

CASE PRESENTATION

A case report of a 14-month-old with a skipped segment involving the distal 50 cm of the small bowel associated with colonic ganglionosis is presented. A current review of the literature is discussed.

CLINICAL DISCUSSION

Our patient had persistent obstructive symptoms despite undergoing a technically good, ganglionic pull-through operation at an outside institution. A laparoscopic-assisted pull-through might have documented a small bowel wall diameter discrepancy.

CONCLUSION

Although rare, skip segment Hirschsprung's disease is a real phenomenon that paediatric surgeons should be aware of and could involve small and large bowels.

Mesenteric Neural Crest Cells Are the Embryological Basis of Skip Segment Hirschsprung's Disease

BACKGROUND & AIMS

Defective rostrocaudal colonization of the gut by vagal neural crest cells (vNCCs) results in Hirschsprung's disease (HSCR), which is characterized by aganglionosis in variable lengths of the distal bowel. Skip segment Hirschsprung's disease (SSHD), referring to a ganglionated segment within an otherwise aganglionic intestine, contradicts HSCR pathogenesis and underscores a significant gap in our understanding of the development of the enteric nervous system. Here, we aimed to identify the embryonic origin of the ganglionic segments in SSHD.

METHODS

Intestinal biopsy specimens from HSCR patients were prepared via the Swiss-roll technique to search for SSHD cases. NCC migration from the neural tube to the gut was spatiotemporally traced using targeted cell lineages and gene manipulation in mice.

RESULTS

After invading the mesentery surrounding the foregut, vNCCs separated into 2 populations: mesenteric NCCs (mNCCs) proceeded to migrate along the mesentery, whereas enteric NCCs invaded the foregut to migrate along the gut. mNCCs not only produced neurons and glia within the gut mesentery, but also continuously complemented the enteric NCC pool. Two new cases of SSHD were identified from 183 HSCR patients, and Ednrb-mutant mice, but not Ret^-/- mice, showed a high incidence rate of SSHD-like phenotypes.

CONCLUSIONS

mNCCs, a subset of vNCCs that migrate into the gut via the gut mesentery to give rise to enteric neurons, could provide an embryologic explanation for SSHD. These findings lead to novel insights into the development of the enteric nervous system and the etiology of HSCR.

Congenital Segmental Intestinal Dilatation: A 25-Year Review with Long-Term Follow-up at the Medical University of Innsbruck, Austria

Background and Aim  Congenital segmental intestinal dilatation (CSID) is a neonatal condition with unclear etiology and pathogenesis. Typically, the newborn with CSID presents with a limited (circumscribed) bowel dilatation, an abrupt transition between normal and dilated segments, neither intrinsic nor extrinsic perilesional obstruction, and no aganglionosis or neuronal intestinal dysplasia. We aimed to review this disease and the long-term follow-up at the Children's Hospital of the Medical University of Innsbruck, Tyrol, Austria. Study Design  Retrospective 25-year review of medical charts, electronic files, and histopathology of neonates with CSID. Results  We identified four infants (three girls and one boy) with CSID. The affected areas included duodenum, ileum, ascending colon, and sigmoid colon. Noteworthy, all patients presented with a cardiovascular defect, of which two required multiple cardiac surgical interventions. Three out of the four patients recovered completely. To date, the three infants are alive. Conclusion  This is the first report of patients with CSID and cardiovascular defects. The clinical and surgical intervention for CSID also requires a thorough cardiologic evaluation in these patients. CSID remains an enigmatic entity pointing to the need for joint forces in identifying common loci for genetic investigations.

Hirschsprung's disease: clinical dysmorphology, genes, micro-RNAs, and future perspectives

On the occasion of the 100th anniversary of Dr. Harald Hirschsprung's death, there is a worldwide significant research effort toward identifying and understanding the role of genes and biochemical pathways involved in the pathogenesis as well as the use of new therapies for the disease harboring his name (Hirschsprung disease, HSCR). HSCR (aganglionic megacolon) is a frequent diagnostic and clinical challenge in perinatology and pediatric surgery, and a major cause of neonatal intestinal obstruction. HSCR is characterized by the absence of ganglia of the enteric nervous system, mostly in the distal gastrointestinal tract. This review focuses on current understanding of genes and pathways associated with HSCR and summarizes recent knowledge related to micro RNAs (miRNAs) and HSCR pathogenesis. While commonly sporadic, Mendelian patterns of inheritance have been described in syndromic cases with HSCR. Although only half of the patients with HSCR have mutations in specific genes related to early embryonic development, recent pathway-based analysis suggests that gene modules with common functions may be associated with HSCR in different populations. This comprehensive profile of functional gene modules may serve as a useful resource for future developmental, biochemical, and genetic studies providing insights into the complex nature of HSCR.

A Retrospective Cohort Study of Total Colonic Aganglionosis: Is the Appendix a Reliable Diagnostic Tool?

Background: Hirschsprung's disease (HD) is characterized by a lack of ganglion cells in the myenteric and submucosal plexus, associated with increased numbers of acetyl cholinesterase (AChE) positive nerve fibres. In approximately 10% of patients with HD the entire colon will be affected; a condition known as Total Colonic Aganglionosis (TCA). Aganglionosis of the appendix has long been considered to be an important finding in a patient in whom TCA is suspected, but its reliability for diagnosis has seldom been discussed. The aim of our study was to assess the reliability of the appendix as a histological specimen for the diagnosis of TCA, and to evaluate the long-term outcome of TCA.

Methods: A retrospective cohort study was performed of all pathological specimens of patients with confirmed HD in our institution between March 2006 and April 2016.

Results: Out of a total of 91 patients identified, 15 patients also had histopathological analysis of the appendix. Nine of these cases were confirmed as having TCA. The remaining 6 patients had HD involving the rest of the bowel up to the ascending colon, with normal ganglion present in the caecum. The appendix was removed in all the 15 cases. All 9 patients with confirmed TCA had aganglionosis of the appendix as well. The remaining 6 cases of short and long segment HD not involving the caecum, demonstrated normal ganglion cells within the appendix.

Conclusion: Aganglionosis of the appendix is a reliable tool in the diagnosis of TCA. The authors recommend that at the time of levelling biopsies, if aganglionosis extends to the mid-transverse colon, an ileostomy be performed and appendix sent for definitive confirmation of TCA. However, at the time of definitive surgery, a frozen section of pull-through segment of bowel is recommended to confirm the presence of ganglion cells.

Distal Rectal Skip-Segment Hirschsprung Disease and the Potential for False-Negative Diagnosis

In skip-segment Hirschsprung disease (SS-HSCR), an aganglionic segment of bowel, which extends proximally from the distal rectum, is interrupted by a ganglionated "skip segment." Skip segments are usually located far proximal to the rectum where they do not interfere with initial diagnosis, although the possibility of distal SS-HSCR should be considered during interpretation of intraoperative biopsies or patients with atypical postoperative courses. We report 2 cases of SS-HSCR with skip areas in the distal rectum, 1 of which led to a false-negative diagnosis by suction rectal biopsy. These 2 cases of SS-HSCR, along with others in the literature, highlight the point that ganglionic skip segments can confuse clinicians and lead to inadequate bowel resection, diagnostic delay, or a false-negative diagnosis. The pathogenesis of SS-HSCR is discussed in light of recent discoveries regarding transmesenteric migration of vagal neural crest cells and the role of sacral neural crest cells in hindgut neurodevelopment.