Congenital pouch colon associated with anorectal malformation-histopathologic evaluation

Although enough literature is available on the descriptive and the management aspects of congenital pouch colon (CPC) associated with anorectal malformation (ARM), there is paucity of its detailed histopathologic studies. The present article details the histopathologic observations in the excised specimens of CPC in the neonates operated on for ARM.

Formalin-fixed specimens of CPC were evaluated both grossly and microscopically. They were stained by H&E stain and Masson trichrome stain.

Haustrations and tenia coli were uniformly absent in all the CPC specimens. Mucosa showed focal erosion, hemorrhage, and disruption in the muscularis mucosae. Submucosa showed congested blood vessels, hemorrhage, and thrombosis. Both the circular and the longitudinal muscle layers showed hypertrophic and atrophic appearance. Both the muscle layers also showed disruption. There was presence of fibrosis in all the muscular layers on Masson trichrome stain. There was presence of unique constriction bands in the muscularis propria. These were seen as focal dipping and narrowing of the muscular layers at intermittent intervals. They were more prominent in the circular muscle layers.

Congenital pouch colon seen in association with ARM is an abnormally developed tissue and needs to be resected for better functional outcome of the remaining gut. However, further physiologic and immunohistochemical studies are warranted to observe the contractile and innervation pattern of CPC.