The epidemiology and enzyme histotopochemical characterization of ultrashort-segment Hirschsprung's disease

Abstract

The enzyme histotopochemical characteristics of ultrashort segment Hirschsprung's disease are described on the basis of 18 cases of this form of impaired motility of the distal rectum, as diagnosed by biopsy in the last 20 years. Unfixed specimens of the rectal segment involved show significantly increased acetylcholinesterase activity in the parasympathetic fibers of the muscularis mucosae alone, the similar change in the lamina propria mucosae characteristic of classical Hirschsprung's disease usually being absent. In strip biopsy specimens of the rectal mucosa taken at the pectinate line, a transition is sometimes observed from aganglionic to normal innervation. The diagnosis of ultrashort segment Hirschsprung's disease may thus be missed if biopsies are taken too high, and it is therefore advisable to take the first biopsy at the pectinate line and further biopsies 1, 2, and 4 cm proximal to it or, alternatively, to take a strip biopsy. Two-thirds of the patients in this series were under 1 year of age at diagnosis, with the remainder between 4 and 21 years. Overall, ultrashort segment Hirschsprung's disease accounted for about 10% of all the cases of aganglionosis of the rectum and rectosigmoid (Hirschsprung's disease) encountered. However, improved knowledge of this particular form of the disease meant that the rate of diagnosis was considerably higher in the second half of the period, at 14% of all cases of aganglionosis and 6.8% of all cases of congenital innervation failures of the gut. The disease is thus relatively rare, though more common than total aganglionosis of the colon (Zuelzer-Wilson syndrome). The sex ratio — five males to one female — is similar to that for classical Hirschsprung's disease. Enzyme histotopochemical staining for acetylcholinesterase activity in the parasympathetic fibers of the rectal mucosa has confirmed beyond all doubt that ultrashort segment Hirschsprung's disease does exist as a special form of aganglionosis of the distal rectum.