Gallbladder
Benign tumors
Pyloric gland adenoma


Topic Completed: 29 October 2019

Revised: 13 November 2019

Copyright: 2019, PathologyOutlines.com, Inc.

PubMed Search: Pyloric gland adenoma gallbladder

Xiaoyan Liao, M.D., Ph.D.
Page views in 2019: 1,927
Page views in 2020 to date: 2,819
Cite this page: Liao X. Pyloric gland adenoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/gallbladderpyloricgland.html. Accessed April 9th, 2020.
Definition / general
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
  • ICD-0: 8140/0 - adenoma, NOS
  • ICD-11: 2E92.6 - benign neoplasm of gallbladder, extrahepatic bile ducts or ampulla of Vater
  • Epidemiology
    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
    Radiology images

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    Transverse ultrasound

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    Sagittal ultrasound

    Prognostic factors
    • If invasive carcinoma is ruled out, PGA is cured by cholecystectomy, even when high-grade dysplasia is present
    Case reports
    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

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    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.
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    Polypoid lesion

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    Eosinophilic cytoplasm

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    Intervening stroma

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    Tightly packed mucinous glands

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    MUC5AC

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    MUC6

    Positive stains
    Negative stains
    Molecular / cytogenetics description
    Molecular / cytogenetics images

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    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?

    1. Aberrant expression of CDX2 is a frequent feature
    2. Frequently shows MUC5AC positivity
    3. It is a precursor lesion for most of the gallbladder adenocarcinomas
    4. Occurs predominantly in males
    5. Usually CK7 positive
    Board review answer #1
    E. Usually CK7 positive (this is a pyloric gland adenoma)

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