RESUMO
The acetylcholinesterase (AChE) activity in Hirschsprung's disease was analyzed for histochemical patterns according to age. Its evolutional nature was also assessed. Two hundred thirty children (0 to 16 years of age) with acute or chronic obstipation were submitted to rectal suction biopsy for AChE histochemical staining. One hundred nineteen of them showed abnormal AChE activity. Retrospective analysis of those cases permitted us to establish three histochemical patterns: Pattern I, thick nerve trunks present only in the submucosa and, characteristically, absence of AChE activity in the lamina propria. This pattern was predominant in newborn up to 3 months of age and was designated the newborn pattern. Pattern II, thin nerve fibers in the muscularis mucosae and submucosa with a clear infiltration in the lamina propria. This pattern was mainly seen in children older than 1 year of age and was called classical pattern. Pattern III, an intermediate pattern showing morphologic characteristics of the two previous patterns with predominance of one or another, according to the age. A prospective study was also made in 15 children with Hirschsprung's disease who were submitted to suction rectal biopsies at different ages. In this study, a clear evolutional character of the AChE activity was observed from the newborn pattern to the intermediate and finally to the classical pattern.
