Gastrointestinal Duplications

GI duplications may be divided into the following types:

• Cervical duplications
• Thoracic and thoracoabdominal duplications
• Gastric duplications
• Duodenal duplications
• Other small-intestine duplications
• Colonic duplications
• Rectal duplications

Cervical duplications are generally duplications of the esophagus. Most esophageal duplications involve the distal esophagus.[3]

In as many as one third of thoracic and thoracoabdominal duplications, there is a second or third duplication cyst below the diaphragm; therefore, computed tomography (CT) should include the abdomen. Almost all patients with thoracic or thoracoabdominal duplications have vertebral anomalies, and the central nervous system (CNS) may be involved. The histologic similarity and anatomic proximity of bronchogenic cysts and intramural esophageal duplications support their common origin.[4]

Gastric duplications are generally cystic. They are generally located on the greater curvature and have no communication to the stomach.

Duodenal duplications generally do not communicate with the intestinal lumen. They can arise from the bile ducts or the pancreas.

Most small-intestine duplications are located in the ileum. Duplications may be cystic or tubular and are located on the mesenteric border, often sharing a common muscular wall and blood supply with the native intestine. Multiple small-intestine duplications may be present.[5]

Cystic colonic duplications may be isolated or may have an external fistula to the skin, urinary tract, or normal colon. Tubular colonic duplications can also occur with duplication or triplication of the colon. Tubular duplication of the colon is often associated with duplication of the anus, vagina, and penis. Multiple short-segment duplications of the colon may also be present.[6]

Rectal duplications occur in the retrorectal space.

Associated anomalies are common with certain duplications, and screening for these anomalies should be performed in appropriate patients. The following are examples:

• Thoracoabdominal duplications - Vertebral anomalies (approximately 75%)
• Enteric cystic duplications - Intestinal atresias
• Tubular hindgut duplications - Genitourinary malformations

GI duplications are most frequently single, tubular, or cystic and are most often located on the mesenteric side of the native alimentary tract structure.[7] Symptoms are often related to the location of the duplication; oral and esophageal lesions can create respiratory difficulties, whereas lower GI lesions may cause nausea, vomiting,[5] bleeding, perforation, or obstruction.[8]

Patients with cervical esophageal duplications or thoracic/thoracoabdominal duplications may present with respiratory distress that is caused by compression of the airway; this can be life-threatening.

The presence of heterotopic mucosa (eg, gastric mucosa) in a duplication can lead to peptic ulcerations, bleeding, and perforation with peritonitis.

Neoplastic changes have been reported in GI duplications.

The true etiology of GI tract duplications is not known.[9] Several theories have been postulated.

The idea that the initial developmental abnormality occurs in the gastrulation stage and results in a split notochord has been proposed. During early embryogenesis, the notochord is open, and the endoderm of the yolk sac and the ectoderm of the notochord are fused; a tube called the neuroenteric canal connects the yolk sac and the amnion.

As part of the development of the split notochord, an endodermal-ectodermal adhesion between the cord has been proposed to result in the persistence of an endomesenchymal tract between the yolk sac and the amnion. The endomesenchymal tract formed is responsible for the anomalies of the entire GI system. However, not all duplications are compatible with this theory, and other etiologies have been proposed.

Some duplications of the foregut and hindgut may result from "partial twinning." These duplications may be associated with other paired structures, such as those found in the genital and urinary tract. Other duplications, especially those of the ileum, may occur as a result of persistent embryologic diverticula. Some portions of the intestinal tract have a solid stage during development; therefore, duplications of these structures may result from "aberrant luminal recanalization." Finally, intrauterine environmental factors, such as trauma or hypoxia during a vascular accident, may cause duplications at any level of the GI tract.

GI duplications are observed in 1 of every 4500 autopsies, predominantly in white males. Synchronous GI duplications occur in as many as 15% of patients. Relative frequencies of the various types are as follows:

• Cervical duplications - Cervical esophageal duplication cysts are the most unusual GI duplication, with fewer than 20 cases reported
• Thoracic and thoracoabdominal duplications - These make up 4% of all GI duplications
• Gastric duplications - These account for 7% of all GI duplications
• Pyloric duplications - These are extremely rare; however, they are reported in the literature ^[10]
• Duodenal duplications - These account for 5% of all GI duplications
• Small-intestine duplications - The small intestine is the most frequent site of GI duplications, accounting for 44% of cases ^[5]
• Colonic duplications - These may be cystic or tubular; they represent 15% percent of duplications
• Rectal duplications - These represent up to 5% of GI duplications ^[11]

In a single-institution review of GI duplications in 72 children, Xiang et al found the ileocecal area to be the site most commonly involved, followed by the colon, jejunum, stomach, and duodenum.[12]

The outcome of surgical (or medical) management of GI duplications is favorable. Metaplastic changes that have been reported in untreated GI duplications can be prevented, depending on the location of the duplication, by appropriate surgical intervention.

The severity and types of malformations associated with GI duplications play a significant role in determining morbidity and mortality.

The presentation of a gastrointestinal (GI) duplication depends on its size and location.[13]

Cervical duplications

Patients with cervical duplications present with respiratory distress that may be life-threatening and necessitates rapid diagnosis and treatment.

Thoracic and thoracoabdominal duplications

Respiratory distress caused by airway compression may be noted in younger children; however, in older patients, heartburn or melena has been reported, which is probably caused by the presence of gastric mucosa in one third of patients with thoracic and thoracoabdominal duplications.

Gastric duplications

Patients usually present when younger than 1 year with vomiting, poor feeding, failure to gain weight, and a palpable mass upon physical examination. Hypertrophic pyloric stenosis is often a misdiagnosis in such infants. The mucosal lining of the cysts is often gastric and can lead to melena or hematemesis.[14] Massive hemorrhage from gastric duplications can occur even in elderly patients.[15]

Duodenal duplications

About 15% of these duplications contain ectopic gastric mucosa, which predisposes the patient to ulceration. Peptic ulceration may lead to painless GI hemorrhage that can progress to perforation. Duplications may extend into the liver or even transdiaphragmatically. These are generally diagnosed after onset of high intestinal obstruction or hemorrhage that may commonly be accompanied by icterus or pancreatitis.

Pyloric duplications

These are extremely rare and can present with signs of gastric outlet obstruction.[16]

Small-intestine duplications

Clinical presentation depends on the type, size, location, and mucosal lining of the duplication.[17] Small cystic duplications can be anchor points for intussusception or can result in volvulus, whereas long tubular duplications with proximal communication drain poorly, and retention of intestinal contents can obstruct adjacent intestine. Distal communication is more common and is more difficult to diagnose than proximal communication.

Gastric mucosa in a duplication can lead to ulceration and perforation. The diagnosis is often not established before surgery. Cecal duplications are rare and may present as an appendicular abscess, a tumor, or necrotizing enterocolitis.[18]

Colonic duplications

Cystic colonic duplications either are asymptomatic or present as abdominal masses that may be accompanied by pain. Bleeding may be observed despite the lower prevalence of ectopic gastric mucosa in colon duplications. Newborns may present with volvulus or acute intestinal obstruction. Tubular colonic duplications are usually asymptomatic, but severe esthetic problems are observed with the duplicated genitalia.

Rectal duplications

Presenting signs of colonic or presacral duplications may include constipation, rectal bleeding, hematochezia, rectal prolapse, hemorrhoids, fistula-in-ano, and perirectal abscess.[11] Rectal duplications may present as unusual external cysts.[19]

Multimodality imaging may facilitate diagnosis.[20] The most common investigative methods used to image duplications are ultrasonography (US) and contrast-medium examinations. However, computed tomography (CT) and magnetic resonance imaging (MRI) can be helpful in difficult cases that require a multiplanar approach.[21]

Thoracic duplications are often apparent on routine chest radiography.[22] They have a characteristic enhancing ring that can be revealed by CT.

Contrast studies are helpful in demonstrating the mass effect and displacement of normal alignment.[23, 21]

In cases of GI bleeding, heterotopic gastric lining can be detected by using technetium scans.[24]

CT may be useful in the diagnosis of duodenal duplications.[25]

US, including endoscopic ultrasonography (EUS),[26]  has been successfully used in diagnosing duplications.[27, 28, 29, 30, 31] In cases of colonic or presacral duplications, US has the added benefit of revealing associated genitourinary anomalies.

Surgical resection is the preferred method of treatment for most gastrointestinal (GI) duplications; however, for duodenal duplications, surgical resection is inadvisable because of the close proximity of such cysts to the biliary and pancreatic ductal system. Patients presenting with complex tubular colonic duplications may not require a surgical approach if internal communication of the duplication is adequate and the colon is normal.

Before treatment begins, GI duplications must be evaluated with respect to their localization in terms of common blood supply and the search for heterotopic gastric mucosa. In cervical esophageal duplications, the trachea must also be evaluated. Similarly, endoscopic evaluation of the genitourinary tract is recommended in selected hindgut duplications.

The preferred treatment of GI duplications is excision[32, 33] ; however, in colonic duplications, which feature communication proximally and distally between the duplication and the normal colon, administration of stool softeners and enemas can improve symptoms.

Because most duplications have a mesenteric location, they share a common blood supply with the normal organ.[34] If feasible, segmental resection may be performed (see the image below). Otherwise, one may excise or "shell out" the cyst if an adequate plane is present. Mucosal stripping has also been described.

If excision is not possible—for example, because of proximity to the biliary or pancreatic ducts—a drainage procedure may be performed. However, if this is planned, one must determine whether gastric mucosa is present (with technetium scan); if so, it must be excised to prevent future ulceration.

In colon and rectal duplications below the peritoneal reflection, endoscopy of the genitourinary tract should be performed preoperatively to rule out associated anomalies.

Laparoscopic approaches to the resection of alimentary tract duplications in children are being described with increasing frequency.[35]

Cervical esophageal duplications

Surgical treatment involves the excision of the cyst. Total mucosectomy is also curative.

Thoracic and thoracoabdominal duplications

Treatment involves excision of the cyst. Combined thoracoabdominal cysts make up fewer than 2% of all duplications. If staged excision is planned, the duplication remaining after the primary excision should have a communication with the GI tract or be drained externally to prevent compression if it expands because of hemorrhagic secretions.

Gastric duplications

In most cases, resection can be accomplished without entering the stomach by resecting the shared wall between the stomach and the duplication. Gastric resection is generally not required.

Laparoscopic resection of gastric duplication cysts has been described in newborns[36]  and in adults.[37]

Duodenal duplications

Surgical resection is the treatment of choice; however, drainage of the duplication cysts into the duodenum or into a Roux limb of the jejunum is an acceptable alternative if a risk of injury to the biliary or pancreatic ductal system is observed.

Preoperative endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiography (PTC), or magnetic resonance cholangiopancreatography (MRCP) should be performed to evaluate the involvement of the biliary and pancreatic ducts. These studies may also distinguish between duodenal duplication and a choledochal cyst if the diagnosis is unclear. Cholangiography may also be performed intraoperatively to characterize the ductal anatomy in relation to the cyst.

Excision should be performed if gastric mucosa is present to avoid later ulceration. Marsupialization and external drainage have no value.

Case reports have described successful treatment of nonmalignant duodenal duplication cysts by means of endoscopic techniques.[38, 39]

Pyloric duplications

These are extremely rare but have been detected upon endoscopic investigation.[40]

Small-intestine duplications

Segmental resection along with the adjacent intestine is the preferred treatment for small cystic or short tubular duplications. Cystic duplications (in the absence of gastric mucosa) that cannot be resected may be drained into a Roux limb. Long tubular duplications that cannot be resected because of their length can be managed by means of intestinal lengthening procedures, mucosal stripping through multiple incisions (when separation is not possible), or diversion into the stomach.

Colonic duplications

Cystic

In cases of smaller cysts, complete excision of the duplication and its attached normal colon is preferred. However, because long colonic duplications generally have an opening to the normal colon, enlarging these internal communications by excising a small part of the common wall to permit reentry from the duplication into the normal colon is sufficient.

Tubular

If the duplication is fused with a normal rectum and perineal anus, the duplication can be connected transanally by excising part of the common rectal wall. Smaller duplications may also be treated by excising the fistula wall, making it part of the common rectum. Tubular duplications may also be treated by excising the lesion with the normal colon, by enlarging existing communications with the normal bowel, or by excising the common wall.

Tubular duplications often extend below the peritoneal reflection, and they are associated with abnormalities of the genitourinary tract. Preoperative cystoscopy and vaginoscopy/hysteroscopy should be performed to identify duplication, fistula, or other abnormalities of the bladder, urethra, or genital tract.

Rectal duplications

The general approach to rectal duplications involves transanal exposure of the cyst, incision of the posterior rectal mucosa, drainage of the cyst, and stripping of the the cyst wall mucosa. Total excision may also be performed via the transanal, posterior sagittal, or transcoccygeal (Kraske) approach.

GI duplications can be found along the entire length of the GI tract; therefore, the complications that may occur after surgical excision of these duplications depend on the location of the lesions.

Untreated GI duplications may lead to the following complications:

• Severe and possibly life-threatening respiratory distress may occur in patients with cervical esophageal duplications
• Ectopic gastric mucosa in a duplication can lead to peptic ulceration, bleeding, perforation, and peritonitis
• Recurrent pancreatitis may occur from gastric duplications communicating with the pancreatic duct
• Neoplastic changes have been reported in patients with untreated GI duplications
• Hematochezia, hemorrhoids, fistulas-in-ano, or anal abscess may recur in patients with untreated rectal duplications

Surgical excision of GI lesions is generally curative; however, follow-up is important after the treatment of certain types of duplications.

Pancreatitis may occur after surgical management of gastric or duodenal duplications because of the proximity of the duplications to the pancreaticobiliary tree.

Recurrent bleeding may occur after mucosal stripping of the duplication in cases where complete excision is not possible.

Patients undergoing medical therapy with stool softeners and who have had cystic colonic duplications require regular clinical evaluation.

Severe duplications of external genitalia associated with tubular colonic duplications pose a cosmetic problem, and counseling is required.

Continence studies (eg, rectal manometry) are advisable for patients who have been treated for rectal duplications.