https://doi.org/10.1351/goldbook.10926
Condition of extreme dilation of the colon that can be congenital (as in Hirschsprung disease) or acquired (as when children refuse to defecate).
Note: Aganglionic megacolon is a condition, where parts of the colon have abnormal motor activity, resulting in spasms and massive distention of the colon proximal to the spasm.