Gallbladder & extrahepatic bile ducts

Gallbladder benign

Pyloric gland adenoma



Last author update: 22 August 2023
Last staff update: 22 August 2023

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PubMed Search: Pyloric gland adenoma

Xiaoyan Liao, M.D., Ph.D.
Page views in 2023: 19,141
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Cite this page: Liao X. Pyloric gland adenoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/gallbladderpyloricgland.html. Accessed July 13th, 2024.
Definition / general
  • Grossly visible, noninvasive neoplasm of the gallbladder composed of uniform back to back mucinous glands arranged in a tubular configuration
  • WHO classification
    • Architecture is often complex
    • Glands are bland looking pyloric type or Brunner gland-like
      • There is minimal cytological atypia in most of the lesions
      • By definition, the cytologic atypia is sufficient for low grade dysplasia
      • Foci of high grade dysplasia can be seen in larger lesions
      • 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 or Brunner gland-like
  • Usually > 0.5 cm and < 2 cm
    • < 0.5 cm should be distinguished from nodular pyloric gland metaplasia, which by definition bears no cytologic atypia or dysplasia
    • > 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-O: 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, pyloric gland adenoma is cured by cholecystectomy, even when high grade dysplasia is present
Case reports
Treatment
  • Surgery (cholecystectomy) is indicated for any polypoid lesions ≥ 1 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 (Histopathology 2018;72:1007)
  • Lined by cuboidal or columnar mucus secreting cells with apical mucinous cytoplasm
  • Round or oval, relatively small, hyperchromatic, basally located nuclei with a small round conspicuous nucleolus
  • Slight nuclear overlapping and increased N:C ratios when compared to background normal glands
  • High grade dysplasia features more complex architecture, prominent nucleoli and loss of nuclear polarity
  • 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

Bland cytologic atypia

Bland cytologic atypia


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MUC5AC

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MUC6

Beta-catenin

Beta catenin

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

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Comparative genomic hybridization

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 a discrete mass
  • Intracholecystic papillary (tubular) neoplasm:
    • Considered an umbrella term for any neoplastic polyps, adenomas and papillary neoplasms that are ≥ 1 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 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 above, which of the following statements 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 style answer #1
E. Usually CK7 positive, as this is a pyloric gland adenoma. Answer A is incorrect because they do not often express CDX2. Answer B is incorrect because they frequently show MUC6 positivity. Answer C is incorrect because it is a precursor lesion to some but not most of the gallbladder adenocarcinomas. Answer D is incorrect because they occur predominantly in female patients.

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Reference: Pyloric gland adenoma
Board review style question #2
Regarding pyloric gland adenoma of the gallbladder, which of the following is correct?

  1. Frequently shows p53 aberrant expression
  2. Lesions > 1 cm can be reclassified as intracholecystic papillary neoplasm
  3. They are not associated with chronic cholecystitis
  4. Those are benign lesions and never progress to cancer
Board review style answer #2
B. Lesions > 1 cm can be reclassified as intracholecystic papillary neoplasm. If the lesion is > 1 cm with dysplasia present, classification as intracholecystic papillary (tubular) neoplasm is recommended by some authors. Answer C is incorrect because pyloric gland adenoma is often associated with background chronic cholecystitis. Answer A is incorrect because p53 usually shows normal wild type expression in those lesions. Answer D is incorrect because they can progress to cancer.

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Reference: Pyloric gland adenoma
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