In Hirschsprung's disease, the diagnosis is confirmed histologically by which finding on full-thickness rectal biopsy, and the colonic segment involved is always aganglionic to which proximal limit in classic (short-segment) disease?

• A Hyperplasia of ganglion cells with abundant nerve fibres; aganglionic segment confined to anus only
• B Absence of Meissner's plexus only with normal Auerbach's plexus; aganglionic up to sigmoid
• C Excess mucin-secreting goblet cells in mucosa; aganglionic from rectum to splenic flexure
• D Absence of ganglion cells in the myenteric (Auerbach's) and submucosal (Meissner's) plexuses with acetylcholinesterase-positive hypertrophic nerve fibres; aganglionic segment extends from the internal anal sphincter to the rectosigmoid junction in 75% of cases ✓

Explanation

Hirschsprung's disease results from failure of craniocaudal neural crest cell migration, causing absence of ganglion cells in both the myenteric (Auerbach's) and submucosal (Meissner's) plexuses of the distal bowel. Histologically, absence of ganglion cells with acetylcholinesterase-positive hypertrophic adrenergic nerve fibres in the lamina propria and muscularis mucosae is pathognomonic. In 75% of cases (classic/short-segment disease), the aganglionic zone extends from the internal anal sphincter to the rectosigmoid junction. Long-segment and total colonic aganglionosis occur in the remaining 25%. Definitive surgery involves pull-through of ganglionic bowel (Swenson, Soave, or Duhamel procedures).

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.