Rectum, Hirschsprung disease, Calretinin stain

Hirschsprung disease is a congenital condition affecting bowel movement. It results from malformation of the enteric nervous system in which there is complete absence of ganglion cells in the myenteric and submucosal plexuses of the terminal rectum. Considered a multigenic disorder with incomplete penetrance, the majority of patients with isolated Hirschsprung disease have mutations in the RET gene. In the sections, note the near complete absence of ganglion cells and abundant hypertrophied nerves. The acetylcholinesterase (ACE) immunostain demonstrates the presence of thick and numerous nerve fibers in the muscularis mucosa and lamina propria, a finding that can confirm the diagnosis. The calretinin immunostain demonstrates the absence of ganglion cells.

This slide shows calretinin stain. See Related Content for H&E and ACE stains.