Imaging Pearls ❯ Pancreas ❯ Heterotopic Pancreas
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- “The upper gastrointestinal tract is the most common location, with gastric and duodenal involvement reported at frequencies of 24–38% and 9–36%, respectively. But it has been identified in other locations, such as the jejunum, liver, gallbladder, colon, appendix, spleen, mesentery, retroperitoneum, female reproductive system, mediastinum, and lungs . Gastric and duodenal ectopic pancreas is most frequently found in the submucosa along the greater curvature of the antrum and in the proximal duodenum, typically with an endophytic growth pattern. The first 50 cm of the jejunum is the third most frequent location, estimated in 0.5–35% of cases. They are also typically located in the submucosa although exophytic growth patterns are more common .”
Pancreatic congenital anomalies and their features on CT and MR imaging: a pictorial review
Gary Amseian . Juan‑Ramon Ayuso
Abdominal Radiology (2024) 49:1734–1746 - “Submucosal heterotopic pancreas can be easily misidentified as gastrointestinal stromal tumors (GIST). Unlike GISTs, which often exhibit exophytic or mixed growth patterns, globular contours, and a well-defined border, ectopic pancreas usually presents with an endoluminal pattern, flat contours, and poorly defined borders, in addition to the previously described characteristics.”
Pancreatic congenital anomalies and their features on CT and MR imaging: a pictorial review
Gary Amseian . Juan‑Ramon Ayuso
Abdominal Radiology (2024) 49:1734–1746 - “Most cases of ectopic pancreas are asymptomatic and are identified incidentally on pathological specimens or during autopsies. However, it can manifest clinically with symptoms resulting from mass effect, such as obstruction or intussusception, as well as underlying pathologies, including ulceration, bleeding, and acute or chronic pancreatitis. Ectopic pancreas is susceptible to the same pathological conditions that affect the normal pancreas. For instance, there have been reported cases of ectopic insulinomas in patients presenting with hypoglycemia. Cystic degeneration and, on rare occasions, malignant transformation can also occur.”
Pancreatic congenital anomalies and their features on CT and MR imaging: a pictorial review
Gary Amseian . Juan‑Ramon Ayuso
Abdominal Radiology (2024) 49:1734–1746
- "Ectopic pancreas, also referred to as heterotopic, accessory, or aberrant pancreas, is defined as pancreatic tissue lacking anatomic and vascular continuity with the main body of the gland; an ectopic pancreas is usually located in the stomach, duodenum, or jejunum. Most of the lesions are small and asymptomatic.”
Ectopic Pancreas: CT Findings with Emphasis on Differentiation from Small Gastrointestinal Stromal Tumor and Leiomyoma
Kim JY et al.
Radiology 2009; 252:92–100 - “Prepyloric antral or duodenal location, endoluminal growth pattern, ill-defined border, promi- nent enhancement of overlying mucosa, and long diameter to short diameter ratio greater than 1.4 were found to be significant CT imaging findings for differentiating ectopic pancreas from other submucosal tumors.”
Ectopic Pancreas: CT Findings with Emphasis on Differentiation from Small Gastrointestinal Stromal Tumor and Leiomyoma
Kim JY et al.
Radiology 2009; 252:92–100 - "Ectopic pancreas may manifest as a submucosal mass in the stomach or duodenum and may easily be misinterpreted as another submucosal tumor such as gastrointestinal stromal tumor (GIST) or leiomyoma on imaging studies or at endoscopic examinations, including endoscopic ultra- sonography (US). Because GISTs are by far the most common submucosal tumors of the stomach and constitute about 90% of gastric submucosal tumors, ectopic pancreas can frequently be mistaken for GIST or leiomyoma at endoscopy, US, or computed tomographic (CT) scanning.”
Ectopic Pancreas: CT Findings with Emphasis on Differentiation from Small Gastrointestinal Stromal Tumor and Leiomyoma
Kim JY et al.
Radiology 2009; 252:92–100 - “In conclusion, ectopic pancreas of the stomach and duodenum has characteris- tic CT findings that differ from those of gastric submucosal tumors such as GIST and leiomyoma. When characteristic CT imaging findings are used in combination, ectopic pancreas can be differentiated from submucosal tumors with a high de- gree of diagnostic accuracy.”
Ectopic Pancreas: CT Findings with Emphasis on Differentiation from Small Gastrointestinal Stromal Tumor and Leiomyoma
Kim JY et al.
Radiology 2009; 252:92–100
- “Heterotopic pancreas is an entity in which pancreatic elements are found outside of the gland proper. In the literature, it is defined as elements without anatomic or vascular connection to the gland. It is overall a relatively uncommon entity with a reported incidence of 0.5%–14% in autopsy series . The true incidence is unknown as most cases are asymptomatic.”
Heterotopic pancreatic rests: imaging features, complications, and unifying concepts Kim DU, Lubner MG, MellnicknV.M. et al. Abdom Radiol (2016). doi:10.1007/s00261-016-0874-9 - “There are two prevailing theories as to the origin of pancreatic heterotopia—migration and metaplasia. In the migration theory, fragments of pancreatic tissue are thought to separate from the developing pancreas during the foregut rotation and deposit in aberrant locations . Proponents of this theory suggest that this could account for the preponderance of ectopic pancreatic tissue in the upper gastrointestinal tract, as the pancreas develops from two buds that arise from the foregut. The metaplasia theory proposes that totipotent endodermal cells give rise to pancreatic tissue in anomalous regions. Molecular abnormalities, such as in the Notch signaling pathway or home box gene expression, have been postulated to play a role in metaplasia.”
Heterotopic pancreatic rests: imaging features, complications, and unifying concepts Kim DU, Lubner MG, MellnicknV.M. et al. Abdom Radiol (2016). doi:10.1007/s00261-016-0874-9 - “The stomach and duodenum have been variably described as the most common sites of involvement with reported frequencies of 24%–38% and 9%–36%, respectively. Gastric lesions are typically located in the antrum, along the greater curvature, within 3–6 cm of the pylorus, while duodenal lesions are located in the proximal portions. Both gastric and duodenal lesions are typically round or ovoid and located in the submucosa with an endophytic growth pattern. Occasionally, heterotopic pancreatic elements have been found in the muscularis propria or serosa.”
Heterotopic pancreatic rests: imaging features, complications, and unifying concepts Kim DU, Lubner MG, MellnicknV.M. et al. Abdom Radiol (2016). doi:10.1007/s00261-016-0874-9 - “Most cases of pancreatic heterotopia are asymptomatic and incidentally discovered. The symptomatic cases are most commonly encountered in 40–50 year old males. The most common symptom is upper abdominal pain with less common symptoms, including nausea, vomiting, weight loss, and jaundice . Symptoms are postulated to be secondary to complications of pancreatic heterotopia, which can be broadly divided into two categories—those possible in any mass, largely determined by location, and those specific to pancreatic tissue.”
Heterotopic pancreatic rests: imaging features, complications, and unifying concepts Kim DU, Lubner MG, MellnicknV.M. et al. Abdom Radiol (2016). doi:10.1007/s00261-016-0874-9 - “Recognition of the atypical radiological presentations of pancreatic pathologic processes, use of optimal imaging techniques such as biphasic imaging of the pancreas (pancreatic parenchymal and portal venous phases) and thin-slice multiplanar reconstruction, and further evaluation with EUS and biopsy in indeterminate cases would help avoiding pitfalls in diagnosis of benign and malignant lesions of the pancreas.”
Pitfalls in pancreatic imaging Kaza RK et al. Semin Roentgenol. 2015 Oct;50(4):320-7 - “Although the typical radiological appear- ances of common pancreatic lesions is well known, there are several potential pitfalls that can be encountered in pancreatic imaging, such as pancreatic anatomical variants mimicking pancreatic lesions, inflammatory conditions mimicking malignancy, atypical radiological appearance of pancreatic adenocarcinoma, and cystic pancreatic lesions and peripancreatic lesions mimicking intrapancreatic lesions.”
Pitfalls in pancreatic imaging Kaza RK et al. Semin Roentgenol. 2015 Oct;50(4):320-7 - “Anatomical variants of the pancreas resulting from anomalies in fusion (pancreas divisum) or migration (annular or ectopic pancreas) are easily recognized by their typical radiological appearance. However, other developmental anomalies such as heterogeneous fatty infiltration, anatomical variants in the shape and contour of the pancreas, and benign intrapancreatic masses such as splenule can mimic pancreatic malignancies.”
Pitfalls in pancreatic imaging Kaza RK et al. Semin Roentgenol. 2015 Oct;50(4):320-7
- “Heterotopic pancreas represents a congenital anomaly where aberrant pancreatic tissue is without ductal or vascular continuity to the gland. The reported incidence ranges from 0.55–13.7%,however, the true incidence is unknown as most patients are asymptomatic and the condition is usually an incidental finding at autopsy or laparotomy. Most ectopic pancreatic tissue is found incidentally during evaluation of other organs. Common sites of involvement include the upper portions of the gastrointestinal tract including the stomach, duodenum, and proximal jejunum.”
Heterotopic pancreas: typical and atypical imaging findings J.W. Kung et al. Clinical Radiology 65 (2010) 403–407 - “However, most individuals remain asymptomatic clinically and are detected during surgery or endoscopy for another evaluation. When symptoms do occur the majority are related to a combination of mass effect and the local and systemic complications of activated pancreatic enzymes.15 Other possible presentations include obstruction from duodenal or pyloric stricture, gastrointestinal hemorrhage, or elevation in serum amylase and lipase..”
Heterotopic pancreas: typical and atypical imaging findings J.W. Kung et al. Clinical Radiology 65 (2010) 403–407 - “Heterotopic pancreas is most often incidentally discovered in the upper gastrointestinal tract, with the stomach
being the most common location. Lesions in the stomach range from 1–3 cm and are usually located along the greater
curvature in the gastric antrum within 6cm of the pylorus.”
Heterotopic pancreas: typical and atypical imaging findings J.W. Kung et al. Clinical Radiology 65 (2010) 403–407 - “At CT a prospective diagnosis of heterotopic pancreas is challenging. Masses are often oval or round with smooth or serrated margins in the gastric antral wall. Often there is homogeneous early enhancement, similar to the normal pancreas. Occasionally, poor enhancement is seen, in which case lesions have been shown to consist primarily of ducts and hypertrophied muscle. A minority of cases show dilatation of heterotopic pancreatic duct.”
Heterotopic pancreas: typical and atypical imaging findings J.W. Kung et al. Clinical Radiology 65 (2010) 403–407