Hypogenesis of intestinal ganglion cells: a rare cause of intestinal obstruction simulating aganglionosis

Isolated hypoganglionosis: results of a nationwide survey in Japan

PURPOSE

This study analyzes how isolated hypoganglionosis (IH) is diagnosed and treated in Japanese pediatric surgical departments.

METHODS

A second questionnaire was sent to 90 pediatric surgical departments that took part in an initial survey on variant Hirschsprung's disease.

RESULTS

Of 109 cases registered as having a certain diagnosis of IH, we targeted 90 patients and excluded the remaining 19. Symptom onset was neonatal ileus with a male:female ratio of 34:56. In most cases, results from radio-contrast enemas and suction rectal biopsies were normal. Anorectal manometry demonstrated that there was no relaxation in 73 % of the 37 patients examined. Furthermore, out of 55 patients who were examined intraoperatively, IH was diagnosed or suspected in 29 cases. Another 12 cases were eventually diagnosed with IH by other institutions using paraffin-embedded specimens. Stomas were initially created in 89 out of 90 cases and the mortality rate of the group that initially received jejunostomies was significantly lower than that of the ileostomy group (p < 0.05).

CONCLUSION

Preoperative diagnosis of IH is often difficult and intraoperative biopsies were only able to provide a correct diagnosis in 52 % of cases. More accurate diagnosis and the initial creation of jejunostomies rather than ileostomies may assist in improving patient management and outcomes.

Differential changes in intrinsic innervation and interstitial cells of Cajal in small bowel atresia in newborns

AIM

To investigate morphological changes of the enteric nervous system (ENS) and the interstitial cells of Cajal (ICCs) in small bowel atresia.

METHODS

Resected small bowel specimens from affected patients (n = 7) were divided into three parts (proximal, atretic, distal). Standard histology and enzyme immunohistochemistry anti-S100, anti-protein gene product (PGP) 9.5, anti-neurofilament (NF), anti-c-kit-receptor (CD117) was carried out on conventional paraffin sections of the proximal and distal part.

RESULTS

The neuronal and glial markers (PGP 9.5, NF, S-100) were expressed in hypertrophied ganglia and nerve fibres within the myenteric and submucosal plexuses. Furthermore, the submucous plexus contained typical giant ganglia. The innervation pattern of the proximal bowel resembled intestinal neuronal dysplasia. The density of myenteric ICCs was clearly reduced in the proximal bowel, whereas a moderate number of muscular ICCs were found. The anti-CD117 immunoreaction revealed additional numerous mast cells. The distal bowel demonstrated normal morphology and density of the ENS, the ICCs and the mast cells.

CONCLUSION

The proximal and distal bowel in small bowel atresia revealed clear changes in morphology and density of the ENS and ICCs.

[Hypoganglionosis as a cause of chronic constipation]

Hypoganglionosis comprises 3-5% of gastrointestinal innervation defects which are connected to therapy-resistant chronic constipation in children and adults. Similar to Hirschsprung's disease, hypoganglionosis may be complicated by megacolon formation and must be considered in the differential diagnosis. Three main subtypes may be distinguished: congenital hypoplastic hypoganglionosis occurs predominantly in Hirschsprung's disease proximal to the aganglionic segment and consists of small paucicellular ganglia with increased interganglionic distances. Oligoneuronal dysganglionic hypoganglionosis manifests in childhood. Initially, myenteric ganglia are of normal size and have normal interganglionic spacing and normal neuronal content. However, nerve cells are hypoplastic and ganglia undergo progressive nerve cell loss. This type of hypoganglionosis may progress into atrophic hypoganglionosis, which shows a morphology similar to hypoplastic hypoganglionosis. All subtypes of hypoganglionosis result in decreased acetylcholinesterase activity in the nerve fiber network of the muscularis propria. The pathogenesis of hypoganglionosis is still poorly understood. In Hirschsprung associated hypoganglionosis, mutations in the RET and GDNF-genes have been found. Despite a heterozygote GDNF+/- animal model for hypoganglionosis, no GDNF mutations have so far been demonstrated in human Hirschsprung independent, isolated hypoganglionosis.

Enteric nervous system and developmental abnormalities in childhood

ENS consists of a complex network of neurons, organised in several plexuses, which interact by means of numerous neurotransmitters. It is capable of modulating the intestinal motility, exocrine and endocrine secretions, microcirculation and immune and inflammatory responses within the gastrointestinal tract, independent of the central nervous system. Though the embryological development of various plexuses are completed by mid-way of gestation, the maturation of neurons and nerve plexuses appear to continue well after birth. Therefore, any histological or functional abnormalities related to the gastrointestinal function must be investigated with the ongoing maturational processes in mind.

Epidemiology of congenital innervation defects of the distal colon

Congenital colorectal innervation defects were evaluated by studying 3699 colonic mucosal biopsy specimens obtained from 773 patients over a 5-year period (1986-1991). In 358 cases (46.3%) a classifiable defect was present, with aganglionosis in 187 of these patients (52.2%) and hypoganglionosis of the colon in 18 (5.0%). Hypoplastic or aplastic sympathetic innervation (type-A neuronal intestinal dysplasia was found in 2.2% (n = 8) and dysplasia of the parasympathetic submucous plexus (type-B neuronal intestinal dysplasia) in 40.6% (n = 145) of the patients with classifiable defects. Identification of a specific innervation defect was not possible in 229 of the 773 patients (29.6%), 28% of whom exhibited slight dysplasia and 30% immaturity or hypogenesis of the submucous plexus. In 40% of the unclassifiable cases heterotopic nerve cells were found in the muscularis mucosae and/or lamina propria mucosae, while 2% had severe heterotopia with the cells of the myenteric plexus completely displaced into the circular and/or longitudinal muscle layers. These patients generally suffered from severe chronic constipation requiring surgical intervention. Four congenital innervation defects of the colorectum can thus be clearly differentiated at present: aganglionosis (in its various forms), hypoganglionosis, type-A neuronal intestinal dysplasia, and type-B neuronal intestinal dysplasia.