Mistakes in ... 2021 - 27

ueg education
Mistakes in... 2021
a
b
Less commonly, large polyps can become
pedunculated and present as gastric outflow
obstruction due to their prolapse through the
pylorus.15
The technique for excision of larger polyps will
depend on their morphology and size. Generally,
endoscopic resection is preferred, with options
including endoscopic mucosal resection (EMR)
and endoscopic submucosal dissection (ESD). An
en-bloc resection with ESD should be considered
for larger sessile polyps (>15mm) due to the risk of
recurrence.
Mistake 5 Not testing and treating for
H. pylori infection
c
d
Both hyperplastic polyps and adenomatous
polyps are associated with H. pylori infection,
which should therefore be tested for and
eradicated whenever a patient has a positive
test result. Diagnosis of H. pylori infection at
endoscopy is done by performing a rapid urease
test, for example the CLO test (campylobacterlike
organism). These are highly reliable
diagnostic tests, with studies showing 80-100%
sensitivity and 97-99% specificity.7
For best
Figure 2 | Fundic glandular and hyperplastic polyps. a | Fundic glandular polyps seen in the corpus and body.
They are either lighter or the same colour as the surrounding mucosa. b | On near view, with image
enhancement, lacy blood vessels are seen through the translucent surface and the surface shows a pattern of
fine grey dots. c | Hyperplastic polyps are smooth, red buttered with whitish exudates (fibrin) and are dome
shaped. d | The surface vascular pattern is more prominent on image enhancement. Reproduced from Banks M,
Graham D, Jansen M, et al. Gut 2019; 68: 1545-1575.17 © Banks et al. (2019). Re-use permitted under CC BY-NC
4.0 license [http://creativecommons.org/licenses/by-nc/4.0/].
vasculature. In a patient who is taking PPIs and
has a normal background stomach, polyps that
have these features are almost diagnostic.
Any polyps that have a mucosal pattern or
morphology not typical of FGPs, or that occur in
the context of an abnormal background stomach,
warrant consideration of an alternative diagnosis.
Mistake 3 Failing to take appropriate
biopsy samples
Gastric polyps detected at endoscopy, including
FGPs, should be biopsied at the first endoscopy
to confirm the diagnosis and exclude dysplasia.1
If there are multiple polyps then not all polyps
but a representative sample need to be biopsied.
Sampling larger polyps >1cm in size with forceps
alone may not be representative of the histology
of the whole polyp, and as such neoplasia may be
missed. A study comparing the histological diagnosis
made at polypectomy with biopsy samples
for polyps >5mm, found complete concordance
for only 55.8% of diagnoses; however, only 2.7% of
biopsy samples missed clinically significant
diagnoses, such as foci of carcinoma. Although
the incidence of clinically significant diagnoses
is low this finding should alert the endoscopist
that gastric polyps, particularly larger ones, can
harbour significant pathology missed at biopsy.12
As the majority of gastric polyps found at
endoscopy in Western practice will be FGPs
occurring on a normal stomach mucosa, routine
sampling of the surrounding mucosa is not
recommended. However, biopsy samples of
the background mucosa should be taken if
hyperplastic or adenomatous polyps are found
(see Mistake 7 for more detail).
Mistake 4 Thinking that size doesn't
matter
Large polyps >1cm in diameter should generally
be removed in their entirity to confirm the
diagnosis, because malignant potential increases
with increasing polyp size. Although FGPs are
generally low risk and rarely exceed this size,
large FGPs (>1cm) can harbour neoplasia.
FGP-associated dysplasia is rare in the case of
sporadic FGPs, with >80% occurring in the
setting of familial adenomatous polyposis
(FAP).13
Estimates of the malignant potential
of hyperplastic polyps vary significantly from
<1-20%. The overall prevalence of carcinoma in
hyperplastic polyps is low (up to 1.8%), but this
rises with increasing polyp size.14
In addition to the increased risk of neoplasia,
larger polyps can develop surface erosions and
blood loss resulting in iron deficiency anaemia.
results, two samples-one from the antrum
(avoiding areas of ulceration and obvious
intestinal metaplasia) and one from normalappearing
corpus-are sufficient and provide
the highest yield.7
The most common reason for
false-negative results is recent PPI use, for this
reason testing after a 2-week break from PPIs is
generally recommended. Histology is another a
reliable way of diagnosing H. pylori infection, with
sensitivity and specificity both as high as 95%
and 99%, respectively. This approach is more
expensive, and to some degree suffers from
interobserver variability, it does, however, provide
additional histological information and should be
generally be reserved for situations where atrophy,
intestinal metaplasia or neoplasia are suspected.
Hyperplastic polyps develop in epithelium
that is regenerating after a chronic inflammatory
stimulus and are seen in the setting of chronic
H. pylori-related gastritis, pernicious anaemia,
and adjacent to ulceration or erosions. For
patients who have small hyperplastic polyps
(<1cm), H. pylori eradication should be
considered before undertaking endoscopic
resection, with a repeat endoscopy performed
3-6 months later, because in many cases these
polyps will regress post eradication.
Gastric adenomas (raised intraepithelial
neoplasia) typically occur in the setting of
H. pylori-related chronic atrophic gastritis
(CAG), and should be viewed as a neoplastic
precursor to adenocarcinoma. Adenomas should
be resected and one must always also test
and treat for H. pylori as both BSG and ESGE
guidelines demonstrate that its eradication is
likely to be linked with a decreased risk of
progression of CAG.5,6
15

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Mistakes in ... 2021

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