An Unusual Case of Gastric Heterotopic Pancreas

Laura Rubbia-Brandt2, Olivier Huber1, Antoine Hadengue2, Jean Louis Frossard2
1Division of Clinical Pathology, Clinic of Digestive Surgery, and 2Division of Gastroenterology
and Hepatology, Geneva University Hospitals. Geneva, Switzerland
ABSTRACT
Context
Submucosal lesions of the
gastrointestinal tract represent a diagnostic
challenge for the physician. Endoscopic
ultrasonography may provide useful
information before deciding on therapeutic
strategy.
Case report We report on a case of a young
female presenting with a large gastric
submucosal mass, 32 mm in size. Endoscopic
ultrasonography
identified
a
non-
homogeneous lesion, with three cystic spaces
suggesting a degenerated gastrointestinal
stromal tumor. An exploratory laparoscopy
was performed. Surprisingly, the final
diagnosis was gastric heterotopic pancreas.
Conclusion Heterotopic pancreas should
always be kept in mind when facing
extramucosal gastric masses, especially in
young people. A perioperative biopsy is
recommended to prevent unnecessary
extensive surgery.
INTRODUCTION
Submucosal lesions of the gastrointestinal
tract usually appear as intraluminal
protrusions with normal overlying mucosa.
Most frequently, these lesions are found
incidentally during routine endoscopy.
Surface biopsies are usually normal. The
differential diagnosis includes a number of
benign and malignant gastric wall tumors,
intramural vessels, and extrinsic compression
from extramural structures [1].
Heterotopic pancreas is a congenital disorder
which consists of the presence of normal
pancreatic tissue located outside the
pancreatic frame [2]. It often remains
asymptomatic throughout life, but may
sometimes cause symptoms including
symptomatic gastrointestinal bleeding, gastric
ulceration, gastric outlet obstruction,
pancreatitis and even malignant degeneration.
CASE REPORT
A 25-year-old woman without a significant
past medical history developed progressive
dyspeptic symptoms over a few weeks
without concomitant weight loss. On physical
examination, the patient was in good health;
bowel sounds were normal and there was no
tenderness in the epigastric area; the liver and
the spleen were not palpable. Blood count and
liver function tests were normal. An upper
gastrointestinal endoscopy was performed and
revealed an intraluminal protrusion with
normal overlying mucosa in the antrum. A
surface biopsy revealed normal mucosa.
Abdominal CT scan showed a polycystic
gastric mass of 32 mm in diameter, without
any
lymphadenopathies.
Endoscopic
ultrasonography (EUS) identified an iso- to
hypoechoic lesion with well-defined margins,
located in the gastric wall and originating
from within the submucosa and the muscular
propria layer (fourth layer). The lesion was

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non-homogeneous, with three cystic spaces,
the largest one being 12 mm in size (Figure
1). There were no lymphadenopathies. From
this information, we postulated that the
patient had a potentially malignant tumor
such as a malignant gastrointestinal stromal
tumor (GIST). EUS-guided fine needle
aspiration was not performed because we
thought that the lesion had already
degenerated. She was then referred to surgery.
An exploratory laparoscopy revealed a 30 mm
cystic tumor located in the posterior wall of
the gastric antrum, with a distal limit 10 mm
from the pylorus. A laparoscopic resection
was performed, with only a 5 mm resection
margin distally, due to the proximity of the
pylorus. Frozen section analysis identified a
heterotopic pancreas. Based on this diagnosis,
no further resection was performed. The
stomach was then closed by continuous
suture. The postoperative course was
uneventful and she was discharged four days
after surgery. The final histological diagnosis
was gastric heterotopic pancreas without any
evidence of malignancy (Figure 2 and 3). The
lesion was composed of exocrine acinar
tissue, ducts and endocrine cells. The cysts
corresponded to a dilated duct with erosions
and inflammation located essentially in the
submucosa and in the muscle layer.
DISCUSSION
The most common locations of heterotopic
pancreas are the stomach, and the small
intestine. Heterotopic pancreas has also been
reported to occur in unusual sites such as the
esophagus, the lungs, the gallbladder and
even the spleen [3, 4, 5]. It has been
suggested that heterotopic pancreas results
from the separation of pancreatic tissue
during the embryonic rotation of the dorsal
and ventral buds. It usually remains
asymptomatic throughout life and is found
incidentally during an upper GI endoscopy or
Figure 1. Endoscopic ultrasonography of the lesion.
Large gastric mass originating from within the
submucosa and muscle layer (yellow arrow) with cystic
spaces (green arrow). Red arrow: normal gastric wall.
Figure 2. Gross examination: Well-delimited mass of
30 mm in size with several cysts located predominantly
in the submucosa (green arrow: mucosa; red arrow:
muscle layer).
Figure 3. High power field magnification (x200)
illustrating acinar and ductal components (green
arrows) surrounding an endocrine aggregate (red
arrow).

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JOP. J Pancreas (Online) 2004; 5(6):484-487.
JOP. Journal of the Pancreas – http://www.joplink.net – Vol. 5, No. 6 – November 2004. [ISSN 1590-8577]
486
other radiological imaging modalities in
patients between 40 and 70 yeas of age [5].
The lesion can sometimes induce abdominal
symptoms. Among these, epigastric pain is
common and seems to be due either to
intussusception of the overlying gastric
mucosa or to pancreatitis [6]. Pancreatic
abscess and the malignant transformation of
heterotopic pancreas have been reported [7].
Gastric lesions are located in the antrum in
85-95% of cases and originate from the
submucosa in two-thirds of cases, the
remaining being localized in the muscularis
mucosae or the subserosal layer [8].
EUS has provided a major breakthrough for
characterizing submucosal lesions [1]. It can
show whether the lesion arises from the
digestive wall or from an extrinsic structure
compressing the gastrointestinal tract. It can
determine the layer of origin of intramural
lesions, an important clue for arriving at a
diagnosis. Stromal cell tumors, for example,
can be seen as developing from the
muscularis propria [9], a feature found in the
present case, while lipomas typically arise
from the submucosa. Specific EUS
characteristics can be helpful in
differentiating between benign and malignant
tumors. One study demonstrated that some
EUS criteria can predict malignancy: a tumor
diameter greater than 4 cm, irregular
extraluminal border, heterogeneity, echogenic
foci, and cystic spaces greater than 4 mm
[10]. Some of these features were found in the
present case.
At EUS, heterotopic pancreas is usually
hypoechoic and heterogeneous with indistinct
margins. It most commonly arises from the
third or fourth layer, or a combination of the
two layers of the GI tract. Anechoic areas
within the lesion correlate with ductal
structures [11].
GISTs are more frequently seen in older
people. At EUS, GISTs are typically
hypoechoic, homogeneous lesions with well-
defined margins, although they can
occasionally have irregular margins and
ulcerations. Most GISTs originate from
within the muscularis propria. Small lesions
may originate from the muscularis mucosa
[10].
Although EUS-guided fine needle aspiration
has been shown to be a valuable tool for
staging such lesions [12, 13, 14], the
multidisciplinary panel of physicians in
charge of the patient decided not to perform it
because it was thought that the lesion had
already degenerated. Performing EUS-guided
fine needle aspiration in this particular patient
might have helped avoid unnecessary surgery.
If a heterotopic pancreas is found during
routine endoscopy, the treatment should be
dictated by the symptoms. If malignancy is
suspected or if the lesion is responsible for a
gastric outlet obstruction, a surgical resection
is indicated. Surgical resection is preferred to
endoscopic mucosal resection when the
muscularis propria is involved.
In conclusion, heterotopic pancreas should
always be kept in mind when facing
extramucosal gastric masses, especially in
young people. A perioperative biopsy is
recommended in order to prevent unnecessary
extensive surgery.
Received August 4th, 2004 - Accepted August
20th, 2004
Keywords
Choristoma;
Diagnosis,
Differential; Endosonography; Pancreas
Abbreviations GIST: gastrointestinal stromal
tumor
Correspondence
Jean Louis Frossard
Division of Gastroenterology
Geneva University Hospital
1211 Geneva 14
Switzerland
Phone: +41-22.372.93.40
Fax: +41-22.372.93.66
E-mail address: jean-louis.frossard@hcuge.ch

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JOP. Journal of the Pancreas – http://www.joplink.net – Vol. 5, No. 6 – November 2004. [ISSN 1590-8577]
487
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