Fourteen-year experience of acetylcholinesterase staining for rectal mucosal biopsy in neonatal Hirschsprung's disease

Background/Purpose: Acetylcholinesterase (AChE) staining of rectal mucosal biopsy specimens is the most important and popular examination for making a definite diagnosis of Hirschsprung's disease. This examination often is performed for patients with constipation in the daily clinic. The results of this examination are reflected immediately in the treatment. However, the authors sometimes encountered difficult cases to diagnose, especially in neonates. Therefore, a retrospective investigation was conducted on the benefits and problems of AChE staining of rectal mucosal biopsy specimens in neonates. Methods: The authors encountered 459 cases (91 neonates) of suspected Hirschsprung's disease, clinically, from April 1986 to March 2000. Mucosal specimens were taken by punch biopsies. Samples were stained by the modified Karnovsky Roots method using rubeanic acid as an amplifier and immediately examined with a light microscope. These results were collected and assessed mainly on neonatal cases. The authors also analyzed the 104 cases of Hirschsprung's disease diagnosed in patients less than 1 year of age to evaluate the relationship between the grade of proliferation of AChE positive fiber and age. Results: Forty-one neonatal cases of Hirschsprung's disease were diagnosed based on the findings of AChE staining. A definite diagnosis of Hirschsprung's disease was confirmed based on the pathologic findings of operative samples. Forty-eight cases that were diagnosed as normal included 4 cases that turned out to be false-negative (3 Hirschspurung's disease cases and 1 case of an allied disorder of Hirschsprung's disease). There were no major complications in mucosal punch biopsy. In the cases of Hirschsprung's disease diagnosed in a patient less than 1 year of age, the grade of AChE-positive fiber tended to increase with the aging of patients. Conclusions: The specificity of AChE staining was high (100%), but its sensitivity was slightly low (91%). Careful long-term follow-up is required for any cases diagnosed as normal. Mucosal biopsies should be repeated in cases of persistent clinical symptoms.