Umbilical Polyp - An Overview

Introduction

The umbilical polyp is a rare congenital lesion caused by the persistence and outgrowth of the mucosa of the gastrointestinal omphalomesenteric duct (OMD) that remains in the umbilicus. The polyp resembles an umbilical granuloma under the microscope and does not disappear after cauterization (procedure of removal using heat) with silver nitrate. The perseverance of enteric mucosa causes intermittent discharge from the umbilicus, which is visible in the first few days of life.

What Is an Umbilical Polyp?

The umbilical polyp is a rare anomaly of OMD mucosa that persists at the umbilicus and is histologically defined by a glandular structure lined by intestinal mucosa in connection with the skin's surface. The umbilical polyp is most commonly found in newborns and older children but can also be found in adults. The umbilical polyp is also detected with the other OMD remnants, such as:

1. Patent duct to the bowel.

2. Sinus tract.

3. Duct cyst (fluid-filled cavity).

4. Meckel's diverticulum (abnormality of the gastrointestinal tract).

5. Obliterated duct (fibrous cord).

Some studies have recommended abdominal cavity exploration to rule out the presence of associated OMD anomalies.

How Does an Umbilical Polyp Form?

The omphalomesenteric duct (OMD) connects the yolk sac to the developing embryo's intestinal tract during the formation of the embryo (embryogenesis). The 1.5-mm embryo at three weeks is a small cell called a blastocyst in which the embryonic ectodermal plate separates into two parts called the amnion and yolk sac. A body stalk then suspends these structures within the blastocyst.

The endodermal yolk sac's roof becomes a part of the embryonic digestive system. The remainder of the sac forms a 0.20 inches in diameter vesicle that may persist throughout pregnancy. Only a narrow tubular structure, the OMD, remains between the developing intestine and the yolk sac by the time the embryo is 6 mm long.

The OMD and body stalk elongate as the amniotic sac grows, forming a tubular structure known as the umbilical cord. By the next stage, the OMD is a solid cord that usually vanishes without a trace. This can result in a Meckel's diverticulum, patent OMD, umbilical cyst, sinus, or polyp if the duct does not become completely dissolved.

The umbilical cord usually sloughs between the sixth and tenth day after birth. By days 12 to 15, a scar has formed over the defect, leading to an umbilical polyp formation.

What Is the Clinical Presentation of an Umbilical Polyp?

It is typically associated in connections with gastric mucosa, intestinal mucosa, and pancreatic tissues; however, ectopic (aberrant position) gastrointestinal mucosa has also been found. The presence of a firm, reddish, discharging polypoid lesion that does not respond to topical silver nitrate application is typical of the clinical presentation.

It is sometimes confused with an umbilical cord granuloma, a pink, soft, velvety mass that forms from excess granulation tissue that remains at the base of the umbilicus after cord separation and usually responds to topical silver nitrate. An umbilical polyp bleeds easily, is resistant to local treatment, is painless, and lasts months to years. In infants, persistent weeping from a cord stump is frequently caused by a patent omphalomesenteric duct.

What Are the Consequences of a Persistent Gastrointestinal Omphalomesenteric Duct (OMD)?

The OMD normally closes between the fifth and seventh weeks of pregnancy, but abnormal closure can result in various anomalies. The persistence of open OMD results in the following:

• Umbilical Fistula - It is an umbilical-enteric fistula that causes fecal discharge and necessitates surgical excision.

• Meckel's Diverticulum - The most common OMD anomaly is a Meckel's diverticulum, which has a two percent incidence and a four to six percent lifetime risk of developing a complication such as bleeding, obstruction, intussusception (intestines slide on one another), diverticulitis, or perforation. A fibrous tract from the intestine to the umbilicus is a less common OMD anomaly that can cause chronic abdominal pain.

• Vitelline Cysts - They are uncommon and usually asymptomatic but can cause acute abdominal pain and intestinal obstruction. Umbilical sinus occurs when the umbilical end of the OMD fails to close, resulting in the formation of a sinus tract of varying lengths containing enteric mucosa and causing chronic discharge.

How Is an Umbilical Polyp Detected and Treated?

• Abdominal Exploration - All patients with an umbilical polyp need an abdominal exploration to avoid complications such as intestinal obstruction and bleeding caused by associated OMD anomalies. Studies have found a 56 percent incidence of associated OMD anomalies in patients with umbilical polyps who underwent abdominal cavity exploration. Some of these patients have a polyp with a deep funnel, which could indicate a connection to the intestine.

• Prophylactic Laparotomy or Laparoscopy - The benefits of a prophylactic laparotomy or laparoscopy to remove an asymptomatic umbilical polyp must be balanced against the risks of the surgical procedure. When an opening at the vertex of an umbilical polyp is discovered, an associated OMD anomaly may be suspected and documented by epistolography or ultrasound. Following polyp excision, all patients have their polyp bases examined and probed. A connection with the intestine is suspected then the peritoneal cavity is explored.

What Are the Complications of Umbilical Polyps?

The presence of an umbilical polyp may indicate a persistent omphalomesenteric duct, which may result in complications such as:

• Intra-gastrointestinal connection leads to gastrointestinal prolapse or herniation (entanglement).

• Communication with the bladder results in persistent urinary discharge.

• Hemorrhage.

• Swelling.

• Pus discharge.

What Is the Differential Diagnosis for Umbilical Polyps?

Correlations with pathologic characteristics are used to differentiate umbilical polyps in children.

The possible diagnoses include various conditions such as:

• Benign fibrous lesions (non-cancerous fibrous lesions).

• Pigmented nevi (discoloration of moles on the skin).

• Polyps are derived from urachal remnants (remains of the fetus's bladder).

• Angiomas (overgrowth of blood vessels or lymphatic vessels).

Conclusion

A rare congenital lesion, an umbilical polyp, is one of the possible developmental anomalies of omphalomesenteric duct remnants. It can sometimes be traced back to a urachal remnant. The abdominal cavity exploration in children with an umbilical polyp does not appear to be necessary. Before surgery, the polyp should be examined to rule out the presence of an opening at the vertex. Ultrasound should be performed if an associated OMD anomaly is suspected. Furthermore, the polyp base should be probed during polyp excision to rule out patent OMD.