The innervation and neuroendocrine cell population of the appendix in total colonic aganglionosis.

There is little published information on changes in the appendix in Hirschsprung's disease despite the presence within the mucosa of nerves and neuroendocrine cells together forming a 'neuroendocrine ganglion'. The innervation and neuroendocrine cell population of 11 appendices (two from patients with total colonic aganglionosis, six from patients with short segment Hirschsprung's disease and three normal controls) were examined using H & E, a standard Grimelius silver stain and immunocytochemistry for S-100 protein, neuron-specific enolase, neurofilament and synaptophysin. Compared with both normal and short segment Hirschsprung's disease controls, the total colonic aganglionosis appendices showed decreased numbers of nerve bundles around the muscle layers and within the submucosa, markedly decreased numbers of smaller fibres within the circular muscle and absence of the finer fibres within the lamina propria. There was no change in the overall number of epithelial neuroendocrine cells but subepithelial neuroendocrine cells, normally found in association with mucosal nerve fibres, were totally absent. The concomitant loss of nerve fibres and neuroendocrine cells from the lamina propria in total colonic aganglionosis suggests a different embryological origin for epithelial and sub-epithelial neuroendocrine cells.