An umbilical polyp is a distal remnant of the omphalomesenteric (vitelline) duct (OMD) that connects the yolk sac to the gut in early fetal life. It is thought to result from failure of involution of the OMD during embryonic development, leading to a remnant of the OMD at the umbilical end without connection to the intestine. It is typically lined by intestinal mucosa and, as a result, tends to have a sticky surface. The lesion is present at birth, but the patient may not present until months later with a nonhealing umbilical remnant with persistent serous seepage or bleeding. Boys are affected more often than girls.

An umbilical polyp requires prompt investigation to rule out deeper anomalies of the OMD, such as cysts, a patent vitellointestinal duct, or an enteroumbilical fistula. Serious complications such as infection, peritonitis, hemorrhage, small bowel evisceration, prolapse, obstruction, perforation, intussusception, volvulus, or hernia may occur when these exist.

Malignant degeneration of umbilical polyps has rarely been reported.