Gallbladder & extrahepatic bile ducts
Gallbladder benign
Pyloric gland adenoma
Author: Xiaoyan Liao, M.D., Ph.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Last author update: 29 October 2019
Last staff update: 1 December 2022 (update in progress)
Copyright: 2019-2023, PathologyOutlines.com, Inc.
PubMed Search: Pyloric gland adenoma gallbladder
Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Etiology | Clinical features | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Molecular / cytogenetics images | Sample pathology report | Differential diagnosis | Board review style question #1 | Board review style answer #1Cite this page: Liao X. Pyloric gland adenoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/gallbladderpyloricgland.html. Accessed March 21st, 2023.
Definition / general
- Grossly visible, noninvasive neoplasm of the gallbladder composed of uniform back to back mucinous glands arranged in a tubular configuration
- WHO Classification of Tumours Editorial Board: WHO Classification of Tumours - Digestive System Tumours (Medicine), 5th Edition, 2019
- Architecture is often complex
- Glands are bland looking pyloric type or Brunner gland-like
- There is minimal cytological atypical in most of the lesion
- Low grade dysplasia is not a required diagnostic criterion
- Foci of high grade dysplasia can be seen in larger specimens
- If lesion is > 1 cm with dysplasia present, classification as intracholecystic papillary (tubular) neoplasm is recommended by some authors (Am J Surg Pathol 2012;36:1279)
Essential features
- Grossly visible, complex, back to back uniform mucinous glands of pyloric type of Brunner glands
- Usually > 0.5 cm and < 2cm
- < 0.5 cm arising in a background of pyloric gland metaplasia in the adjacent mucosa should not be designated as pyloric gland adenoma
- > 1 cm with dysplasia may be classified as intracholecystic papillary (tubular) neoplasm
Terminology
- Intracholecystic papillary tubular neoplasm, gastric pyloric, simple mucinous type
ICD coding
Epidemiology
- Found in 0.1 - 10% of gallbladders removed for cholelithiasis or chronic cholecystitis (Cancer 1982;50:2226, J Gastroenterol 1994;29:61)
- Accounts for ~ 82% of gallbladder adenomas (Hum Pathol 2012;43:1506)
- M=F (Am J Surg Pathol 2018;42:1237)
- Mean age of 62.8 years (Am J Surg Pathol 2018;42:1237)
Sites
- No specific site preference reported
- Can occur in the cystic duct with malignant transformation (BMC Cancer 2012;12:570)
Etiology
- 50 - 65% associated with cholelithiasis (Hum Pathol 2012;43:1506)
- Commonly associated with pyloric gland metaplasia, which is possibly a precursor
Clinical features
- Usually asymptomatic and is an incidental finding
- When arising in the gallbladder neck, can lead to gallbladder distension and right upper quadrant pain
Radiology description
- Abdominal ultrasound is usually performed and shows polyps within the gallbladder (J Gastrointest Oncol 2016;7:S81)
Radiology images
Images hosted on other servers:
Transverse ultrasound
Sagittal ultrasound
Prognostic factors
- If invasive carcinoma is ruled out, PGA is cured by cholecystectomy, even when high-grade dysplasia is present
Case reports
- 37 year woman patient with dyspeptic complaints found to have a 2 cm polypoid lesion (Turk J Gastroenterol 2014;25:234)
- 40 year old and 53 year old men each presented with a 1 cm polyp (J Gastrointest Oncol 2016;7:S81)
- 44 year old man with upper abdominal pain found to have a 2 cm polyp (Gastroenterology 2011;141:e3)
- 62 year old man with a 2 cm tumor with transition into well differentiated adenocarcinoma and high grade biliary intraepithelial neoplasia (BMC Cancer 2012;12:570)
Treatment
- Surgery (cholecystectomy) is indicated for any polypoid lesions ≥ 1.0 cm
Gross description
- < 2 cm, sessile or pedunculated
- Usually single but can be multiple
Gross images
Images hosted on other servers:
Intraluminal tumor
Microscopic (histologic) description
- Tightly packed bland looking pyloric type or Brunner gland-like glands
- Lined by cuboidal or columnar mucus secreting cells with apical mucinous cytoplasm
- Round or oval, relatively small, hyperpchromatic nuclei with a parabasal location
- Some glands may be cystically dilated
- There is minimal or no intervening stroma
- Paneth cells and neuroendocrine cells are often present
Microscopic (histologic) images
Contributed by Xiaoyan Liao, M.D.
Polypoid lesion
Eosinophilic cytoplasm
Intervening stroma
Tightly packed mucinous glands
MUC5AC
MUC6
Positive stains
- CK7 and MUC6 (diffuse and strong)
- Nuclear beta catenin reported (Am J Surg Pathol 2018;42:1237)
Negative stains
- MUC2, MUC5AC and CDX2 usually negative or only focally positive (Am J Surg Pathol 2018;42:1237)
Molecular / cytogenetics description
- CTNNB1 mutations detected in 60% and 100% in two separate studies (Hum Pathol 1999;30:21, Am J Surg Pathol 2018;42:1237)
- KRAS mutation reported in a subset (Hum Pathol 1999;30:21, Am J Surg Pathol 2018;42:1237)
- TP53 and GNAS mutations usually not identified
Molecular / cytogenetics images
Images hosted on other servers:
CGH
Sample pathology report
- Gallbladder, cholecystectomy:
- Pyloric gland adenoma
- Gallbladder, cholecystectomy:
- Pyloric gland adenoma with focal high grade dysplasia
Differential diagnosis
- Pyloric gland metaplasia
- Size is the most important criteria; metaplasia is usually < 0.5 cm and does not form discrete mass
- Intracholecystic papillary (tubular) neoplasm
- Considered an umbrella term for any neoplastic polyps, adenomas and papillary neoplasms that are ≥ 1.0 cm
- Can be further divided into several categories by morphology
- Biliary, gastric, intestinal and oncocytic
- Pyloric gland adenoma is currently not included under this umbrella
- However, terms may be interchangeable between intracholecystic papillary (tubular) neoplasm and pyloric gland adenomas that are ≥ 1.0 cm with invasive carcinoma
Board review style question #1
- A polypoid lesion of the gallbladder is identified by ultrasound and is resected. Based on the photomicrograph, which of the following statements about it is true?
- Aberrant expression of CDX2 is a frequent feature
- Frequently shows MUC5AC positivity
- It is a precursor lesion for most of the gallbladder adenocarcinomas
- Occurs predominantly in males
- Usually CK7 positive
Board review style answer #1
E. Usually CK7 positive (this is a pyloric gland adenoma)
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Reference: Pyloric gland adenoma
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Reference: Pyloric gland adenoma
