| Abstract: | In colonic motility disorders, a pathohistological diagnosis based solely on formalin-fixed gut is often inconclusive. Classical histological techniques or immunohistochemistry represent a static staining. In contrast, native tissue submitted to enzyme histochemistry provides functional information about the effectiveness of the cellular performance. Routinely, a complementary set of reactions is performed and includes acetylcholinesterase (AChE), lactic and succinic dehydrogenase, as well as nitroxide synthase reactions. In this monograph, the whole spectrum of different anomalies of the colonic wall is illustrated in a systematic fashion: Hirschsprung's disease is characterized by an increase in AChE activity of parasympathetic nerve fibers of the rectosigmoid. In ultrashort Hirschsprung's disease, only enzyme histochemistry renders a reliable diagnosis possible in biopsies of the anal ring. Aganglionosis of the musculus corrugator cutis ani shows a localized increase of AChE activity in nerve fibers, similar to Hirschsprung's disease, not detectable in conventional histology. Immaturity, hypoganglionosis and neuronal dysganglionosis can be clearly recognized in dehydrogenase reactions. Enzyme histochemical reactions are complemented by picrosirius red staining for assessment of the collagen texture of the muscularis propria. Absence or intertenial interruption of the continuous connective tissue layer between circular and longitudinal muscle of the muscularis propria has been termed aplastic or atrophic desmosis, respectively. Many of the entities described are also observed in adults. Atrophic hypoganglionosis or atrophic desmosis with loss of the myenteric plexus connective tissue fascia is implied as a frequent cause of chronic constipation in adults. The essential contribution of a functional histopathological technique towards a reliable diagnosis of gut dysfunction in native tissue is extensively demonstrated in great detail in more than two hundred figures. |
