Reevaluation of Acetylcholinesterase Staining for the Diagnosis of Hirschsprung Disease and Allied Disorders

Objectives: Acetylcholinesterase (AChE) staining has become the gold standard for definitively diagnosing Hirschsprung disease (HD), although some pitfalls have been reported. We reevaluated a large series at our institute in order to validate the accuracy of AChE staining for detecting HD. Methods: A retrospective study of the rectal mucosal specimens of all of the children with suspected HD during a 13-year period was performed. The specimens were stained according to the modified Karnovsky-Roots method for AChE staining. The final diagnosis, prognosis, and management after the histopathological diagnosis were analyzed with a questionnaire sent to the patient's original hospital. Results: Three hundred and fifty-eight specimens were collected. One hundred twenty-two (34%) specimens were diagnosed as HD, 198 (55%) as nonHD, 25 (7%) as "undetermined,'' and 13 (4%) as "inappropriate.'' The non-HD group contained 190 (96%) specimens with a normal appearance and 8 (4%) specimens with suspected intestinal neuronal dysplasia (IND). Three hundred and six of 358 questionnaires were returned. The final diagnosis showed that no specimens first diagnosed as HD were identified as non-HD and vice versa, for a sensitivity and specificity of 100%. Four cases were finally diagnosed as chronic idiopathic intestinal pseudo-obstruction (CIIP) in the non-HD group. All of the patients with HD underwent radical surgery. Most non-HD patients were managed conservatively, although some continued to have constipation. Conclusions: AChE staining is an accurate tool for differentiating between HD and non-HD with high sensitivity and specificity. CIIP can be included in cases of non-HD; therefore, careful follow-up is mandatory.