Enteric duplication cysts (EDCs) are rare congenital malformations originating from the gastrointestinal (GI) tract. They can manifest anywhere along the digestive system, from the esophagus to the rectum. While often discovered in infancy or early childhood, understanding this diagnosis involves recognizing its structure, varied clinical presentation, and specific methods for identification and treatment.
Understanding Enteric Duplication Cysts
An enteric duplication cyst is a congenital anomaly that arises during the early stages of fetal development, specifically between the fourth and eighth weeks of gestation. This is when the primitive gut tube forms and undergoes recanalization. The cyst is essentially a segment of the bowel that failed to fully separate from the main intestinal lumen.
The term “enteric” refers to the intestines and the broader GI tract, indicating the tissue origin of the malformation. For a structure to be definitively classified as an enteric duplication cyst, it must meet specific pathological criteria. First, its wall must contain layers of smooth muscle, which is a characteristic feature of the normal intestinal wall.
Second, the cyst must be lined with a type of mucosa derived from the GI tract. These cysts are typically closed, blind-ending sacs that do not communicate with the main lumen of the intestine, though some rarer forms are tubular and maintain a connection. While these malformations can occur anywhere, they are most frequently found within the small intestine, with the ileum being the most common site of occurrence.
Manifestations and Clinical Signs
The clinical presentation of an enteric duplication cyst varies depending on the cyst’s size, location, and whether it contains abnormal tissue. Since most cases are identified in infants and young children, symptoms often relate to mechanical interference with intestinal function. A common presentation is intestinal obstruction, which can cause vomiting, abdominal distension, and feeding intolerance.
In some instances, the mass effect of the growing cyst can be felt by a clinician during a physical examination, presenting as a palpable abdominal mass. Acute gastrointestinal bleeding is another significant way the condition may present, often seen as dark, bloody stools called hematochezia or melena. This bleeding is frequently linked to a specific pathological feature: the presence of ectopic gastric mucosa within the cyst lining.
This ectopic tissue secretes acid and digestive enzymes. This caustic material can lead to ulceration of the cyst’s inner wall and the adjacent normal bowel tissue, resulting in significant blood loss. Though less common, EDCs can also be found in adults, where they may be an incidental finding during imaging for an unrelated issue, or they can cause chronic abdominal pain, or lead to complications like intussusception.
Identifying the Cyst
Following the observation of clinical signs, imaging techniques are used to confirm the presence of the enteric duplication cyst. Ultrasound is typically the first-line imaging modality, particularly in pediatric patients, because it is non-invasive and readily available. A characteristic finding on ultrasound is the “gut wall signature” or “double wall sign,” which identifies the cyst wall’s distinct layers.
This signature consists of an inner hyperechoic (bright) layer representing the mucosa and submucosa, surrounded by an outer hypoechoic (dark) layer corresponding to the smooth muscle coat. For more detailed anatomical mapping, especially when planning for surgical intervention, cross-sectional imaging such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) may be used. These scans help surgeons understand the cyst’s relationship to surrounding organs and blood vessels.
A specialized nuclear medicine test, the Technetium-99m pertechnetate scan—often called a Meckel’s scan—is used to specifically identify the presence of ectopic gastric mucosa. This radiotracer is selectively taken up by the acid-secreting cells of the stomach lining. If the cyst contains this ectopic tissue, the scan will show a distinct area of radiotracer uptake outside the stomach, confirming the source of potential bleeding.
Treatment and Long-Term Recovery
The definitive management for an enteric duplication cyst is surgical removal (complete excision). This approach is recommended even for cysts discovered incidentally and not yet causing symptoms. The rationale for intervention is to prevent serious complications, such as intestinal obstruction, uncontrolled hemorrhage, rupture, or, rarely, malignant transformation later in life.
The surgery can often be performed using minimally invasive laparoscopic techniques, which typically results in a faster recovery. During the procedure, the surgeon aims to remove the entire cyst while preserving the adjacent normal bowel. However, in cases where the cyst shares a common blood supply with the segment of adjacent normal intestine, a portion of that normal bowel must also be removed, a procedure called resection and anastomosis.
In complex situations, such as a cyst located near the duodenum or biliary tree, complete excision may risk damage to these structures. In these instances, the surgeon may elect to strip the internal mucosal lining from the cyst wall or create an internal drainage pathway into the intestine. Following successful surgical removal, the long-term outlook is favorable, with a very low risk of recurrence.