Small intestine & ampulla

Congenital anomalies

Heterotopic gastric mucosa


Editorial Board Member: Aaron R. Huber, D.O.
Deputy Editor-in-Chief: Catherine E. Hagen, M.D.
Aastha Chauhan, M.D.
Khalid Amin, M.D.

Topic Completed: 7 June 2021

Minor changes: 7 June 2021

Copyright: 2003-2021, PathologyOutlines.com, Inc.

PubMed Search: Heterotopic gastric mucosa[TI] small intestine

Aastha Chauhan, M.D.
Khalid Amin, M.D.
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Cite this page: Chauhan A, Amin K. Heterotopic gastric mucosa. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/smallbowelheterotopicgastric.html. Accessed December 3rd, 2021.
Definition / general
  • Mature gastric tissue found outside the stomach
  • Gastric fundic heterotopia represents a developmental anomaly and is frequently associated with Meckel diverticulum
Essential features
  • Developmental anomaly characterized by ectopic gastric mucosa outside the stomach
  • Histologically composed of foveolar epithelium with specialized antral glands with or without oxyntic mucosa
  • Clinical features can vary from asymptomatic to abdominal pain, obstruction, intussusception, perforation, palpable mass, ulceration, stricture, etc., depending on the site
  • Treatment is surgical removal of ectopic mucosa for symptomatic lesions
Terminology
  • Heterotopic gastric mucosa (HGM) or ectopic gastric mucosa
ICD coding
  • ICD-10:
    • Q40.2 - other specified congenital malformations of stomach
    • Q43.3 - congenital malformations of intestinal fixation
Epidemiology
Sites
  • Can be found in oral cavity, esophagus, duodenum, jejunum, ileum, rectum, anal canal, gallbladder and bile duct
  • Occurrence in the small intestine is rare unless associated with remnants of Meckel diverticulum (Case Rep Gastroenterol 2020;14:609)
  • Commonly occurs in the first and second portion of the duodenum (Int J Clin Exp Pathol 2012;5:46)
Pathophysiology
  • Error in the differentiation of pluripotent primitive endoderm stem cells could lead to the gastric mucosa being present anywhere throughout the gastrointestinal tract
  • CDX2 stimulates markers of enterocyte differentiation; null mutation of CDX2 can lead to the development of ectopic lesions with a gastric phenotype in the midgut endoderm (J Cell Biol 1997;139:1553)
Etiology
  • Mainly a congenital malformation
Clinical features
  • Symptoms caused by gastric heterotopia depend on location, as well as size of the heterotopic tissue
  • In the majority of cases, patients are asymptomatic due to the small size of the lesion and diagnosis is made incidentally on endoscopy performed for other indications
  • In both small and large intestines, it can give rise to abdominal pain, obstruction, intussusception, perforation, palpable mass, ulceration, stricture, bleeding per rectum and anemia (J Pediatr Surg 2008;43:e19)
Diagnosis
  • These heterotopic lesions cannot be accurately diagnosed by imaging or endoscopic visualization due to lack of specific features, rendering histopathologic examination as the gold standard for precise diagnosis
Radiology description
  • CT scan, fluoroscopy, capsule endoscopy and 99mTc pertechnetate scan can usually detect heterotopic gastric mucosa
  • Capsule endoscopies have been shown to be superior compared with other radiological investigations, including barium contrast studies, computed tomographic enteroclysis, push enteroscopy and MRI
  • Reference: Medicine (Baltimore) 2017;96:e5854
Radiology images

Images hosted on other servers:

33 year old man with HGM in ileum

12 year old girl with extensive HGM

Prognostic factors
  • Patients with extensive heterotopia are at increased risk of adverse outcome, including massive hemorrhage or rarely death (Pediatr Dev Pathol 2000;3:277)
Case reports
Treatment
  • Surgery is the treatment of choice, whether it is carried out by laparoscopy or laparotomy
  • Intraoperative gamma counter use has also been reported as a useful method of localizing bowel segments with nonpalpable areas of heterotopic gastric mucosa for resection (J Pediatr Surg 2001;36:1720)
Gross description
  • Can present as a polypoidal lesion leading to intestinal obstruction, intussusception
Gross images

Case #124

Intraluminal polyp



Images hosted on other servers:

33 year old man with HGM in ileum

14 year old boy with HGM in ileum

Microscopic (histologic) description
  • Lesions consist of full mucosal thickness of specialized gastric glands characterized by chief and parietal cells and surface lined by gastric foveolar epithelium
    • Histologically, oxyntic mucosa may not be seen in all cases of gastric heterotopia
  • Prevalence and risk of malignant transformation of heterotopic gastric mucosa are not entirely understood (J Pediatr Gastroenterol Nutr 2010;50:329)
    • Some reports have described heterotopic gastric mucosa progressing to malignancy in the esophagus, gallbladder and rectum (Korean J Pathol 2013;47:289)
  • Presence of H. pylori organism in heterotopic gastric mucosa in Meckel diverticulum is a rare histological finding; in the last 22 years, 12 published reports were found that specifically looked into the presence of H. pylori in a heterotopic gastric mucosa in a Meckel diverticulum (Clin Med Insights Case Rep 2019;12:1179547619846088)
Microscopic (histologic) images

Contributed by Khalid Amin, M.D.
Ileal polypoid lesion

Ileal polypoid lesion

Gastric glands Gastric glands

Gastric glands

Jejunal polypoid lesion

Jejunal polypoid lesion

Underlying antral glands

Underlying antral glands

Molecular / cytogenetics description
  • Altered expression of cell cycle molecules (the CIP / KIP family) can be associated with heterotopic gastric mucosa (Ann Gastroenterol 2013;26:184)
Sample pathology report
  • Polyp, duodenum, polypectomy:
    • Consistent with gastric heterotopic mucosa
Differential diagnosis
  • Gastric metaplasia:
    • Characterized by gastric foveolar epithelium and absence of specialized antral glands seen in heterotopic gastric mucosa
Board review style question #1
Which of the following statements about gastric heterotopia is true?

  1. Always a sequelae of chronic inflammation
  2. Can be associated with null mutation in CDX2 gene
  3. Microscopy shows gastric foveolar epithelium with absence of specialized gastric glands
  4. No malignant potential
Board review style answer #1
B. Can be associated with null mutation in CDX2 gene

Comment Here

Reference: Heterotopic gastric mucosa
Board review style question #2

Which organism can colonize heterotopic gastric mucosa?

  1. Crytosporidium
  2. Helicobacter pylori
  3. Tropheryma whipplei
  4. Trypansosoma cruzi
Board review style answer #2
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