Pancreas

Congenital anomalies

Heterotopic pancreas



Last author update: 27 April 2022
Last staff update: 27 April 2022

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PubMed Search: Heterotopic pancreas

Kenechukwu Ojukwu, M.D., M.P.P.
Danielle Hutchings, M.D.
Page views in 2021: 5,195
Page views in 2022 to date: 3,812
Cite this page: Ojukwu K, Hutchings D. Heterotopic pancreas. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pancreasheterotopic.html. Accessed August 17th, 2022.
Definition / general
  • Pancreatic tissue that is anatomically separate from the main pancreatic gland and has no vascular or ductal connection to it
Essential features
  • Pancreatic tissue that is anatomically separate from the main pancreatic gland and has no ductal or vascular connections to it the main pancreatic gland
  • Composed of a variable mixture of pancreatic acini, ducts and islets
  • Most common in stomach but may occur throughout GI tract; and rarely in extragastrointestinal sites
  • Often incidental finding
  • May develop the same diseases as the main pancreatic gland (e.g., pancreatitis or pancreatic neoplasms)
  • May be asymptomatic or depending on size and location, may present with symptoms such as abdominal pain, GI bleed or obstruction
  • Surgical management if symptomatic or if diagnosis is unknown
Terminology
  • Ectopic pancreas, heterotopic pancreas, pancreatic rest, accessory pancreas, aberrant pancreas, pancreatic choristoma
ICD coding
  • ICD-10: Q45.3 - other congenital malformations of pancreas and duct
Epidemiology
  • M:F = 3:1
  • Most commonly identified in fifth to sixth decades of life
  • Incidence of 0.5 - 13% in autopsy studies
  • Incidental finding in 0.2 - 0.9% of upper abdominal surgeries and gastrectomies, respectively
  • Reference: Gastroenterology Res 2021;14:45
Sites
Pathophysiology
Clinical features
Diagnosis
  • Frequently is an incidental finding
  • Radiographically, typically appears as ovoid intramural mass (Radiographics 2017;37:484)
  • Endoscopically presents as a solid submucosal mass (Radiographics 2017;37:484)
  • Definitive diagnosis requires histologic examination
Laboratory
Radiology description
Radiology images

Images hosted on other servers:

Gastric submucosal mass

Duodenal and gastric lesions

MRI lesion in duodenum

Prognostic factors
  • Overall good prognosis but with potential to vary, depending on disease state of heterotopic tissue
  • Patients with adenocarcinoma arising in pancreatic heterotopia may do better, compared to those with tumors arising in the main gland (BMC Surg 2017;17:53)
Case reports
Treatment
  • Surgery, if symptomatic
Clinical images

Contributed by Kenechukwu Ojukwu, M.D., M.P.P. and Stephanie Dreikorn, M.D.
Endoscopy, subtle ectopic pancreas

Endoscopy, subtle ectopic pancreas



Images hosted on other servers:

Single balloon
enteroscopy
showing
submucosal lesion

Gross description
  • Usually is a submucosal based lesion but may involve other layers of GI tract (Hum Pathol 2016;55:135)
  • Well demarcated borders with vaguely lobular appearance (Hum Pathol 2016;55:135)
  • On cut surface, typically appears pale yellowish white in color with solid and firm consistency (Hum Pathol 2016;55:135)
  • Central mucosal dimple (opening of pancreatic ducts) may be visible
Gross images

Contributed by Kenechukwu Ojukwu, M.D., M.P.P. and Danielle Hutchings, M.D.
Heterotopic pancreas in Meckel Diverticulum

Heterotopic pancreas in Meckel diverticulum

Heterotopic pancreas in stomach

Heterotopic pancreas in stomach

Microscopic (histologic) description
  • In GI tract, typically centered in submucosa but may involve other layers
  • Rarely may involve extragastrointestinal sites
  • Variable mixture of pancreatic acini, ducts, islets
  • May contain hypertrophic smooth muscle bundles
  • 4 types of pancreatic heterotopia, originally described by Heinrich in 1909 and modified in 1973 by Gasper-Fuentes (Radiographics 2017;37:484):
    • Type 1:
      • Contains all elements of normal pancreatic tissue (acini, ducts and islets)
    • Type 2:
      • Acini and ducts (no islets) in Heinrich classification
      • Ducts only in Gasper-Fuentes classification
    • Type 3:
      • Ducts only in Heinrich classification
      • Acini only in Gasper-Fuentes classification
    • Type 4:
  • May show the same pathologic changes as the main gland, including acute or chronic pancreatitis, pseudocyst formation or neoplasia
Microscopic (histologic) images

Contributed by Kenechukwu Ojukwu, M.D., M.P.P. and Danielle Hutchings, M.D.

Pancreatic heterotopia in the stomach
Submucosal lesion, lobular architecture

Submucosal lesion, lobular architecture

Pancreatic acini and ducts

Pancreatic acini and ducts

Heterotopic pancreas predominantly ducts

Heterotopic pancreas predominantly ducts

Branching ectopic pancreatic ducts

Branching ectopic pancreatic ducts

Ducts, acini and islets

Ducts, acini and islets


Intraductal papillary mucinous neoplasm (IPMN)

Intraductal papillary mucinous neoplasm (IPMN)

Gastric type IPMN

Gastric type IPMN

IPMN, low grade dysplasia

IPMN, low grade dysplasia

Meckel diverticulum with heterotopia

Meckel diverticulum with heterotopia

Virtual slides

Images hosted on other servers:

Heterotopic pancreas presenting as gastric polyp

Cytology description
  • Predominantly pancreatic acini: polygonal cells with abundant granular cytoplasm and eccentric nuclei
  • Ductal structures: cuboidal to columnar cells, honeycomb sheets
  • Islet cells usually not seen
  • Reference: World J Gastroenterol 2015;21:2367
Cytology images

Images hosted on other servers:

Cell block with normal pancreatic acini

Benign pancreatic
acinar cells and
ductal epithelium
(Diff-Quik)

Positive stains
Sample pathology report
  • Gastric antrum, endoscopic mucosal resection:
    • Pancreatic heterotopia involving submucosa and focally mucosa
    • Overlying unremarkable antral mucosa
Differential diagnosis
  • Pancreatic metaplasia:
    • Involves mucosa
    • Acinar cells only, no ducts or islet cells present
  • Adenocarcinoma:
    • Duct predominant heterotopia may show branching pattern and be mistaken at low power for adenocarcinoma
    • Adenocarcinoma shows infiltrative growth, irregular glands, desmoplasia and cytologic atypia
Board review style question #1

A 22 year old woman presents with abdominal pain and is found to have an ileal lesion on imaging. A small bowel resection is performed and shows the image above. What is the most likely diagnosis?

  1. Acute appendicitis
  2. Endometriosis
  3. Meckel diverticulum
  4. Well differentiated neuroendocrine tumor
Board review style answer #1
C. Meckel diverticulum with pancreatic and gastric heterotopia

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Reference: Heterotopic pancreas
Board review style question #2
Heterotopic pancreas Heterotopic pancreas


A 55 year old man presents with persistent anemia, abdominal pain and intermittent melena. Endoscopy reveals a subepithelial gastric antral mass with overlying umbilicated mucosa. Endoscopic mucosal resection shows the images above. What is the most likely diagnosis?

  1. Gastric adenocarcinoma
  2. Heterotopic pancreas
  3. Metastatic adenocarcinoma
  4. Pancreatic metaplasia
Board review style answer #2
B. Heterotopic pancreas

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Reference: Heterotopic pancreas
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