Variants of Hirschsprung Disease

Abstract

Variants of Hirschsprung disease (HD) are a group of conditions that clinically resemble HD despite the presence of ganglion cells in rectal suction biopsies. The characterization and differentiation of various entities is mainly based on histological and immunohistochemical findings of biopsies from patients with functional intestinal obstruction. Over the last decades, several groups have focused on the investigation and definition of variantHDsuch as intestinal neuronal dysplasia, isolated hyperganglionosis, internal anal sphincter achalasia, immature ganglia, and smooth muscle cell disorders such as megacystis microcolon intestinal hypoperistalsis syndrome.However, definition of the above-mentioned entities remains a controversial issue and research is ongoing to standardize diagnostic criteria, specific therapy, and outcome criteria. This chapter summarizes the current knowledge of the above-mentioned entities of variant HD.