Case 4 -
Pyloric Gland Adenoma
University of Chicago Medical Center
Click on slide thumbnail images for an enlarged view.
If you have any difficulties viewing these slides, email the webmaster.
The patient is an 80 year old woman with a history of hematemesis. Esophagogastroduodenoscopy
demonstrated a polypoid mass arising in the gastric cardia that measured 10 cm in greatest dimension.
The remainder of the stomach appeared atrophic endoscopically. The esophagus and duodenum appeared
normal. The polypoid lesion was removed endoscopically in a piecemeal fashion.
The specimen consisted grossly of a total of twelve fragments of pink-tan and red papillary friable
tissue ranging in size from 1.0 to 4.0 cm in greatest dimension. Histologically, the lesion appeared
lobulated, and demonstrated foci of erosion which were presumed to represent the sites of bleeding. The
polyp was comprised of closely packed glands lined by a simple columnar epithelium. In most areas, these
epithelial cells had abundant eosinophilic to amphophilic cytoplasm and round, uniform nuclei aligned
along the basement membrane. The nuclear chromatin was open, and most nuclei contained a prominent
nucleolus. In occasional foci, the nuclei appeared somewhat more elongated, crowded and stratified.
Mitotic figures were readily seen throughout the lesion. No distinct cytoplasmic mucin droplets were
identifiable. The lamina propria surrounding the glands was somewhat edematous, but otherwise
unremarkable. The adjacent gastric mucosa showed evidence of atrophic fundic gastritis with patchy
The differential diagnosis in this case includes all gastric epithelial polyps:
- Fundic gland polyp
- Hyperplastic polyp
- Juvenile polyp
- Cronkhite-Canada polyp
- Peutz-Jeghers polyp
- Isolated hamartomatous polyp
- Gastric adenoma
- Intestinal type adenoma
- Gastric foveolar type adenoma
- Pyloric gland adenoma
Pyloric gland adenoma
Pyloric Gland Adenoma - Discussion
Pyloric gland adenoma is a relatively rare lesion that most commonly arises in the stomach
one study, 85% of pyloric gland adenomas arose in this site, and overall comprised 2.7% of all gastric
polyps (excluding fundic gland polyps)
. There are, however, few reported cases in the literature,
suggesting that this lesion is likely underrecognized by pathologists. Approximately 15% of pyloric
gland adenomas also occur in extragastric sites including the gallbladder, pancreatic ductal system,
uterine cervix and in Barrett's esophagus and heterotopic gastric tissues in the duodenum and rectum
Gastric pyloric gland adenomas tend to arise in the elderly (average age at diagnosis is 73 years),
and are more common in women than in men
Most arise in the body of the stomach, but they may
also occur in the cardia or antrum
The surrounding gastric mucosa often shows evidence of
autoimmune atrophic fundic gastritis or H. pylori gastritis
rare cases is the adjacent gastric mucosa normal.
Pyloric gland adenomas are often relatively large at the time of diagnosis. The mean diameter in one
study was 16.1 + 9.1 mm . Histologically, they are comprised of closely packed pyloric
gland-type tubules or glands lined by a single layer of columnar or cuboidal epithelium. The cytoplasm
is eosinophilic or amphophilic, and often has a "ground-glass" appearance. Mucin droplets are not
identifiable in the cytoplasm. Nuclei are characteristically round, and may or may not contain easily
By immunohistochemistry, pyloric gland adenomas characteristically express MUC6 (a marker of pyloric
gland mucin) and MUC5AC (a foveolar mucin marker)
The intestinal mucin MUC2 and the intestinal
marker CDX2 are generally not expressed in pyloric gland adenomas
One study did demonstrate
aberrant expression of CDX2 in a series of gallbladder pyloric gland adenomas .
Dysplasia is common in pyloric gland adenomas. In one study, 37% of cases showed no evidence of
dysplasia, 12% showed low grade dysplastic changes, and 51% of cases demonstrated high grade dysplasia or
invasive adenocarcinoma .
In the large series reported by Vieth , adenocarcinoma was identified in
30% of cases. These foci of carcinoma were generally small, and usually limited to the mucosa. Others
have also reported a high frequency of associated gastric adenocarcinoma .
Little is known regarding prognosis in patients with pyloric gland adenoma since most studies have not
reported follow-up data. Chen et al  had follow-up on 7 of their 36 patients. In three cases, deeply
invasive carcinoma was identified subsequent to the diagnosis of pyloric gland adenoma (2 cases from the
stomach and one from duodenum). All three patients were alive; the two with gastric lesions at 2 and 10
months post-op, and the third with recent recurrence of carcinoma 10 years after Whipple resection.
Another two patients had residual dysplasia on follow-up, and one additional patient had no evidence of
residual adenoma. In one patient without dysplasia, the lesion persisted, but remained histologically
bland. Our patient has no evidence of residual or recurrent adenoma 9 months post endoscopic mucosal
Pyloric gland adenomas are most easily mistaken for a strange form of gastric hyperplastic polyp.
Like pyloric gland adenomas, hyperplastic polyps often arise in a background of atrophic gastritis. It
is believed that hyperplastic represent an exuberant regenerative response of gastric foveolar cells.
The gastric glands themselves do not usually participate in the formation of this type of polyp. Two
major features categorize hyperplastic polyps. The first is marked elongation, infolding, and branching
of the gastric pits leading to a corkscrew or serrated appearance. Tall mucin-secreting foveolar cells
line exaggerated, elongated, and distorted pits that extend from the surface deep into the stroma.
Hypertrophic foveolar cells resembling goblet cells can be present. The pits also dilate to form
variably sized and shaped cysts, which can be quite prominent. Glandular epithelium may be found in the
deeper parts of the polyps. The glands are often antral in type, even when the polyps arise in the body
or fundus. In contrast, pyloric gland adenomas, are not comprised of foveolar-type cells with prominent
apical cytoplasmic mucin droplets, and characteristically display a cytoplasmic "ground-glass"
Foveolar type gastric adenomas may also be confused with pyloric gland adenomas, but these also are
made up of cells resembling foveolar epithelium similar to that of hyperplastic polyps. The nuclei of
the foveolar-type gastric adenomas, however, appear hyperchromatic and dysplastic . These lesions
usually arise in gastric mucosa which does not show evidence of atrophy or intestinal metaplasia. It is
important to distinguish foveolar-type and pyloric gland adenomas because the latter likely have a higher
risk for high grade dysplasia or invasive adenocarcinoma .
Fundic gland polyps are the most common type of gastric polyp encountered by pathologists since these
lesions are frequently seen in patients on proton-pump inhibitor therapy. Fundic gland polyps are
localized hyperplastic expansions of the deep glandular compartment of the oxyntic mucosa. The overlying
pits appear shortened or absent. They contain cystically dilated, irregularly deformed oxyntic glands
with or without glandular proliferations, increased smooth muscle in the lamina propria, and a lack of
hyperplastic foveolar cells. Unlike pyloric gland adenomas which are made up of a single cell type, the
glands of fundic gland polyps are lined by a mixture of parietal, chief, and mucous neck cells.
Intestinal type gastric adenomas resemble their counterparts in the colon. They often contain
scattered goblet or Paneth cells, and like pyloric gland adenomas, arise in association with atrophic
gastritis and intestinal metaplasia. Flat dysplasia is also frequently seen in the gastric mucosa
surrounding intestinal-type gastric adenomas .
Hamartomatous polyps are usually not easily confused with pyloric gland adenomas. Isolated gastric
hamartomatous polyps consist of a prominent submucosal mass of haphazardly arranged oxyntic glands in a
framework of smooth muscle tissue and occasional focal accumulations of mature lymphoid tissue. The
entire lesion is supported by normal lamina propria. The glands may appear normal or be cystically
dilated. One also sees mucous cells resembling foveolar epithelium as well as rare antral or
cardiac-type glands containing endocrine cells indigenous to the mucosal site. The lesions differ from
those seen in Peutz-Jeghers syndrome, which are usually not submucosal lesions but more mucosally based
with possible submucosal extensions. In gastric Peutz-Jeghers polyps, the epithelial component consists
of foveolar and pyloric glandular cells. Like their counterparts in the colon, gastric Peutz-Jeghers
polyps may lack the arborizing smooth muscle bundles typical of small intestinal lesions. When the
smooth muscle bundles are absent, gastric Peutz-Jeghers polyps may resemble gastric hyperplastic polyps.
Gastric polyps develop in patients with Cronkhite-Canada syndrome. These polyps are broad-based
sessile lesions that contain corkscrew-shaped glands lined by foveolar type epithelial cells. Smooth
muscle fibers extend up into the mucosa. The polyps contain an expanded, edematous lamina propria and
distended, cystic glands lined by flattened epithelium, variable edema, and chronic inflammation.
Gastric polyps tend to occur in the antrum forming hyperplastic gastric folds, some of which mimic
Gastric juvenile polyps consist of hyperplastic foveolae and edematous stroma with inflammatory cells,
and may also resembling gastric hyperplastic polyps. They also resemble the polyps seen in
Cronkhite-Canada syndrome. A definitive diagnosis requires knowledge of the clinical background of the
patient, including patient age, symptoms, distribution of the polyps, the number of polyps, and
associated extraintestinal manifestations. Dysplasia and carcinoma may develop in these lesions.
- Pyloric gland adenomas are relatively rare lesions that most commonly arise in the stomach, and are probably under-recognized by pathologists.
- Pyloric adenomas are often relatively large (1.5-2.0cm) at the time of discovery.
- Dysplasia and foci of adenocarcinoma are common in pyloric gland adenomas.
- Vieth M, Kushima R, Borchard F, Stolte M. Pyloric gland adenoma: a clinico-pathological analysis of 90 cases. Virchows Arch 2003;442: 317-321.
- Chen ZM, Scudiere JR, Abraham SC, Montgomery E. Pyloric gland adenoma. An entity distinct from gastric foveolar type adenoma. Am J Surg Pathol, 2008, e-pub ahead of press.
- Kushima R, Remmele W, Stolte M, Borchard F. Pyloric gland type adenoma of the gallbladder with squamoid spindle cell metaplasia. Pathol Res Pract 1996;192:963-969.
- Fukatsu H, Kawamoto H, Tsutsumi K, et al. Intraductal tubular adenoma, pyloric gland-type, of the pancreas. Endoscopy 2007;39 (suppl 1):E88-89.
- Nakayama Y, Inoue H, Hamada Y, et al. Intraductal tubular adenoma of the pancreas, pyloric gland type: a clinicopathologic and immunohistochemical study of 6 cases. Am J Surg Pathol 2005;29:607-616.
- Amaris J. Intraductal mucinous papillary tumor and pyloric gland adenoma of the pancreas. Gastrointest Endosc 2002; 56:441-444.
- Mikami Y, Hata S, Fujiwara K, et al. Florid endocervical glandular hyperplasia with intestinal and pyloric gland metaplasia: worrisome benign mimic of "adenoma malignum". Gynecol Oncol 1999;74:504-511.
- Kushima R, Vieth M, Mukaisho K, et al. Pyloric gland adenoma arising in Barrett's esophagus with mucin immunohistochemical and molecular cytogenetic evaluation. Virchows Arch 2005;446:537-541.
- Kushima R, Ruthlein HJ, Stolte M, et al. Pyloric gland-type adenoma arising in heterotopic gastric mucosa of the duodenum with dysplastic progression of the gastric type. Virchows Arch 1999;435:452-457.
- Vieth M, Kushima R, de Jonge JP, et al. Adenoma with gastric differentiation (so-called pyloric gland adenoma) in a heterotopic gastric corpus mucosa in the rectum. Virchows Arch 2005;446:542-545.
- Kushima R, Vieth M, Borchard F, et al. Gastric-type well-differentiated adenocarcinoma and pyloric gland adenoma of the stomach. Gastric Cancer 2006;9:177-184.
- Wani Y, Notohara K, Fujisawa M. Aberrant expression of an "intestinal marker" Cdx2 in pyloric gland adenoma of the gallbladder. Virchows Arch 2008;453:521-527.
- Nagata S, Ajioka Y, Nishikura K, et al. Co-expression of gastric and biliary phenotype in pyloric-gland type adenoma of the gallbladder: immunohistochemical analysis of mucin profile and CD10. Oncol Rep 2007;17:721-729.
- Abraham SC, Montgomery EA, Singh VK, et al. Gastric adenomas. Intestinal-type and gastric-type adenomas differ in the risk of adenocarcinoma and presence of background mucosal pathology. Am J Surg Pathol 2002;26:1276-1285.