Rectal biopsy: is it really necessary in anorectal malformations?

The coexistence of Hirschsprung's disease (HD) with anorectal malformation (ARM) is rare but many surgeons still ask pathologists to look for ganglia in the terminal rectum or fistula. In this study, we aimed to highlight the rarity of this association and question the necessity of histological evaluation.

After obtaining board review approval, rectal specimens of ARM patients who underwent corrective surgery in the last 8 years were re-analyzed by two blinded pathologists for the presence and structure of ganglia. Clinical and radiological data of patients retrieved from center records and correlated with histopathologic findings.

67 patients with ARM were identified, distal rectal specimen was obtained in 47. The median age at the time of surgery was 11 months (2 days-59 months). A normal pattern of ganglia was present in 51.1% (24/47), 29.7% (14/47) had aganglionosis and 19.1% (9/47) were inconclusive due to insufficient material. None of the aganglionic specimens showed other histological findings of HD. Patients were followed up regularly in the outpatient colorectal clinic for a median of 87 months (42-117 m). Only 6 experienced severe constipation (3 ganglionic, 2 no biopsy, 1 aganglionic), all of whom responded to a bowel management program, and none developed other manifestations of HD (abdominal distension, failure to thrive or enterocolitis) or required additional surgery.

Our results strongly suggest that the association of ARM and HD is extremely rare and the practice of searching for ganglia in the distal rectum or fistula of ARM patients should be discouraged to avoid potential misdiagnosis and overtreatment.