Radiological presentation and localization
Ectopic pancreatic tissue can be found in various parts of the gastrointestinal tract; however, on X-ray examination, it is most commonly visualized in the area of the greater curvature of the gastric antrum.
On contrast-enhanced radiographs, this anomaly typically presents as a solitary lesion. It appears as a well-circumscribed submucosal nodule, the size of which in the overwhelming majority of cases does not exceed 2 centimeters.
Pathognomonic sign and differential diagnosis
The classic, pathognomonic radiological sign of an ectopic pancreas is a central umbilication on the surface of the nodule.
- During the examination, barium sulfate flows into and pools within this depression.
- This contrast pooling is considered to represent the rudimentary duct of the aberrant gland.
- This sign is present in approximately 50% of patients.
Differential diagnosis directly depends on the presence or absence of this umbilication. If the central pit is not visualized, the ectopic nodule is visually completely indistinguishable from any other small submucosal gastric lesions. In cases where the central barium pooling is very distinct, mucosal ulceration (ulcer defect) should be considered as the primary alternative in the differential diagnosis.
Related topic: Diagnostic imaging of the operated stomach
In addition to congenital anomalies, diagnostic radiologists regularly have to evaluate the stomach postoperatively. Surgeries are most commonly performed for neoplasms, to bypass obstruction, as antireflux measures, and for weight loss (bariatric surgery). Bariatric surgery is indicated for a body mass index (BMI) $\ge$ 30 kg/m$^2$ and comorbid conditions (stroke, heart disease, apnea, type 2 diabetes mellitus).
Main types of procedures encountered by the radiologist:
- Laparoscopic sleeve gastrectomy (LSG) — removal of a large portion of the stomach along the long axis of the greater curvature to form a sleeve. The mechanism is based on volume restriction and removal of cells in the gastric fundus that produce the appetite hormone ghrelin.
- Roux-en-Y gastric bypass (LRYGB) — creation of a small pouch (10–30 ml) to which a mobilized segment of the jejunum (Roux limb) is anastomosed in an end-to-side fashion. The Roux limb can be positioned retrocolically (through a mesenteric defect) or antecolically.
- Gastric banding — placement of an adjustable silicone band around the gastric fundus, 3 cm below the gastroesophageal junction.
Visualization of bariatric surgery complications
Complications following gastric surgeries are divided into early and late. The main methods for detecting them remain fluoroscopy and multislice CT (MSCT).
- Complications after sleeve gastrectomy (LSG): staple line leak may occur in the early period (found in 1–3% of cases and is a frequent cause of hemorrhage) or abscess. In the late period — strictures, nutritional deficiency, and reflux (GERD).
- Complications after gastric bypass (LRYGB): anastomotic leaks, strictures, or anastomotic dilation are characteristic. Due to inadequate vagotomy, 3–10% of patients develop marginal ulceration (more commonly in the first 2 cm of the jejunum). A formidable complication is small bowel obstruction due to internal hernias (e.g., Petersen's hernia). The best CT sign of an internal hernia is the mesenteric "whirlpool" sign.
- Complications of gastric banding: improper placement or early slippage of the band, and in the long-term period — pouch dilation, gastric wall erosion, and herniation through the band (anterior or posterior slippage with eccentric pouch enlargement).
Briefly: answers to topical questions
What other common locations of ectopic pancreas exist in the GI tract besides the gastric antrum?
The provided materials mention the localization of ectopic pancreatic tissue in duodenal diverticula. These diverticula most commonly arise from the medial wall of the duodenum and sometimes contain ectopic pancreatic, gastric, or other functioning tissue.
Other localizations are not mentioned in the provided materials.
What direct radiological signs indicate a staple line leak after bariatric surgery?
A direct radiological sign of a staple line leak is the escape of contrast medium beyond the gastric contour.
- Contrast extravasation (sleeve leak) — visualized during single-contrast upper GI fluoroscopy.
Typically, this sign is identified along the proximal segment of the staple line in the region of the gastric fundus (fundus).
What are the anatomical boundaries of the defect in Petersen's hernia formation?
Petersen's internal hernia forms in the space posterior to the Roux limb.
The exact anatomical boundaries of this space are not specified in the provided materials. The best CT sign of internal hernias is the mesenteric "whirlpool" sign.
Class and exam questions
Where is an ectopic pancreas most commonly localized in the stomach?
In the vast majority of cases, it is found along the greater curvature of the gastric antrum.
Which radiological sign allows differentiation of heterotopia from other submucosal nodules?
The presence of a central umbilication where barium pools. This pooling is considered to represent the rudimentary duct, but it occurs in only 50% of patients.
What should an ectopic gland be differentiated from when there is prominent central barium pooling?
When there is prominent contrast pooling in the center of the nodule, the presentation must be differentiated from mucosal ulceration (ulcer).
What else to study on this topic
- Technique of barium fluoroscopy in suspected submucosal lesions
- CT semiotics of internal hernias and the mesenteric "whirlpool" sign
- Radiological workup algorithm in suspected staple line leak
- Biliopancreatic limb obstruction: MSCT diagnostics
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