Topographic Pecularities of the Submucous Plexus in the Human Anorectum - Consequences for Histopathologic Evaluation of Rectal Biopsies

Abstract

Chronic colorectal motility disorders are commonly encountered in the pediatric population. While most cases can be managed successfully by conservative therapy, a subgroup of patients suffers from severe constipation and requires further diagnostic procedures to identify the underlying pathologies, such as aganglionosis, hypoganglionosis or intestinal neuronal dysplasia (IND). The present study provides reference data about the quantitative distribution of nerve cells and ganglia within the submucosal plexus of the human anorectum from healthy subjects. Anorectal specimens (n = 15) obtained postmortem were divided into 6 segments beginning from the dentate line (S1 = 0-2 cm, S 2 = 2-4 cm, S3 = 4-6 cm, S4 = 6-8 cm, S5 = 8-10 cm, S6 = 10-12 cm). From each segment sections (6 microm thickness) were immunostained with a pan-neuronal marker (Protein Gene Product 9.5) to visualize the enteric nervous system. A morphometric analysis was carried out for each segment recording the number of ganglia and nerve cells of the submucous plexus. Neither ganglia nor nerve cells showed a uniform distribution pattern, but decreased continuously towards the anus. However, even the lowest segments (S1, S2) contained nerve cells and were not aganglionic. In the remaining segments ganglia with 7 or more nerve cells could be detected. The findings demonstrate segment-specific quantitative differences of the anorectal submucous plexus which should be taken into consideration for the histopathologic evaluation of rectal biopsies. Moreover, the data support the concept of a physiologic hypoganglionosis of the anal canal.

Hirschsprung's Disease, One of the Most Difficult Diagnoses in Pediatric Surgery: A Review of the Problems from Clinical Practice to the Bench

“…A reliable diagnosis using a hematoxylin-eosin morphological examination of mucosal biopsies is very difficult because the submucosal ganglia are very small (3 -5 cells per ganglion) and spread inside the Meissner's plexus. These anatomical findings explain the low reliability and false positive results of classical histomorphological (H&E) studies of suction rectal biopsies in suspected HSCR cases [46,47,71]. In 1972, Meier-Ruge [49] started to investigate the acetylcholinesterase (AChE) enzyme-histochemical reaction and revealed a markedly increased AChE activity in a large number of cholinergic nerve fibers and thick nerve trunks present in HSCR.…”

Contrast Enema for Hirschsprung Disease Investigation: Diagnostic Accuracy and Validity for Subsequent Diagnostic and Surgical Planning

“…This zone reaches different levels above the dentate line: 10-25 mm for submucosal, while only 5 mm for the myenteric plexus. [28][29][30] As the near-fullthickness rectal biopsies also contain the myenteric plexus, they can be taken closer to the dentate line, and can therefore diagnose a very short segment HD more reliably than suction biopsies. [28][29][30] Furthermore, 9 to 17% suction biopsies are reported to be inadequate by most large series, principally due to insufficiently included submucosa, which increases the risk for false diagnosis and the necessity to rebiopsy.…”

“…[28][29][30] As the near-fullthickness rectal biopsies also contain the myenteric plexus, they can be taken closer to the dentate line, and can therefore diagnose a very short segment HD more reliably than suction biopsies. [28][29][30] Furthermore, 9 to 17% suction biopsies are reported to be inadequate by most large series, principally due to insufficiently included submucosa, which increases the risk for false diagnosis and the necessity to rebiopsy. 24,28,31,32 A further disadvantage of suction biopsies is the limited size of obtainable specimen and the difficulty of accurate positioning of the suction biopsy device, especially in a moving child.…”

Enteric nervous system

“…In contrast, Iwase et al [60] reported a decrease in the number of myenteric neurons in colonic diverticular disease. This is highlighted in the study by Tafazzoli et al [61] who demonstrated segment-specific quantitative differences of the anorectal submucous plexus which must be taken into consideration for the histopathologic evaluation of rectal biopsies. This is highlighted in the study by Tafazzoli et al [61] who demonstrated segment-specific quantitative differences of the anorectal submucous plexus which must be taken into consideration for the histopathologic evaluation of rectal biopsies.…”