Gallbladder & extrahepatic bile ducts

Gallbladder benign

Intracholecystic tubular nonmucinous neoplasm (ICTN)


Editorial Board Member: Aaron R. Huber, D.O.
Deputy Editor-in-Chief: Catherine E. Hagen, M.D.
Burcin Pehlivanoglu, M.D.
Volkan Adsay, M.D.

Topic Completed: 22 July 2021

Minor changes: 22 July 2021

Copyright: 2021, PathologyOutlines.com, Inc.

PubMed Search: Pyloric gland adenoma gallbladder

Burcin Pehlivanoglu, M.D.
Volkan Adsay, M.D.
Page views in 2020: 641
Page views in 2021 to date: 2,040
Cite this page: Pehlivanoglu B, Adsay V. Intracholecystic tubular nonmucinous neoplasm (ICTN). PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/gallbladderICTN.html. Accessed September 21st, 2021.
Definition / general
  • Noninvasive epithelial neoplasm of the gallbladder that forms pedunculated polyps composed exclusively of small, nonmucinous tubules, often with squamoid morules (Virchows Arch 2021;478:435)
  • Despite the cytoarchitectural complexity that warrants high grade dysplasia diagnosis, almost never associated with invasion (Virchows Arch 2021;478:435)
Essential features
  • Pedunculated, typically solitary polyps with cauliflower architecture composed of lobules of back to back small acinar-like tubular units; possible association with cholesterol polyps
  • Morules are common but can be subtle; they can be highlighted by beta catenin nuclear labeling
  • Usually no dysplasia in the background gallbladder, uninvolved gallbladder is typically devoid of inflammation or chronic changes
  • Virtually no association with invasive carcinoma (unlike other preinvasive neoplasia of the gallbladder) (Virchows Arch 2021;478:435)
    • Does not appear to have field effect risk for biliary tract
Terminology
ICD coding
  • No specific ICD code present; can be regarded under adenoma or intracholecystic papillary neoplasms
  • ICD-O: 8503/2 - intracystic papillary neoplasm with high grade intraepithelial neoplasia
Epidemiology
Sites
Pathophysiology
Etiology
Clinical features
Diagnosis
  • Polyp identified on imaging studies; histology is confirmed after resection
Radiology description
Radiology images

Images hosted on other servers:

Abdominal ultrasound

Prognostic factors
  • Excellent prognosis (Virchows Arch 2021;478:435)
  • Hybrid lesions with both ICTN morphology and mucinous areas may be associated with invasive carcinoma (Am J Surg Pathol 2012;36:1279)
    • Should be classified as intracholecystic papillary neoplasm
  • Proper sampling to exclude associated lesions or invasive carcinoma is warranted regardless, although both are rare
Case reports
Treatment
Gross description
  • Most observed as detached intraluminal nodules or hemorrhagic debris / fibrin
  • Typically present as pedunculated polyps with thin stalks
  • Cauliflower architecture resembling cholesterol polyps
  • Reference: Virchows Arch 2021;478:435
Microscopic (histologic) description
  • Pedunculated polyps; nodular lesion in the lumen; the nodules often have normal epithelial covering
  • Predominantly tubular, occasionally tubulopapillary architecture
    • Compact, back to back small tubular units with minimal lumen
    • Neoplastic cells have round nuclei with prominent nucleoli and scant cytoplasm
    • Some show nuclei with washed out chromatin resembling papillary thyroid carcinoma
    • Squamoid / meningothelial-like morules (> 60%)
    • Amorphous amyloid-like hyalinization zones may be present in the stroma
    • Cholesterolosis in the polyp and often in the uninvolved gallbladder
    • Scattered neuroendocrine cells
  • High grade dysplasia (HGD) by default of complexity but the background mucosa is typically devoid of any pathology, including dysplasia
  • Usually no significant inflammation in the remaining gallbladder
  • Lesions with a mucinous component should be evaluated separately
  • Reference: Virchows Arch 2021;478:435
Microscopic (histologic) images

Contributed by Burcin Pehlivanoglu, M.D. and Volkan Adsay, M.D.

Detached polyp in the lumen

Back to back, small nonmucinous tubules

Back to back, nonmucinous tubules

High grade dysplasia


Squamoid morules

Amyloid-like material in the stroma

Nuclei reminiscent of papillary thyroid carcinoma

Cholesterolosis in the stroma

Cholesterolosis in the background gallbladder


Nuclear beta catenin staining

MUC6 staining

MUC1 staining

MUC5AC

MUC2

Scattered neuroendocrine cells

Positive stains
Negative stains
Molecular / cytogenetics description
Sample pathology report
  • Gallbladder, cholecystectomy:
    • Intracholecystic tubular nonmucinous neoplasm (ICTN) (see comment)
    • No dysplasia identified in the remainder of the gallbladder
    • No invasive carcinoma is identified
    • Cholesterolosis (if present)
    • Comment: Although there is high grade dysplasia within the lesion, intracholecystic tubular nonmucinous neoplasm (ICTN) typically has an innocuous behavior and does not seem to bear any risk for invasive carcinoma in the gallbladder or biliary tract.
Differential diagnosis
Board review style question #1

Which of the following is true about intracholecystic tubular nonmucinous neoplasm (ICTN) of the gallbladder?

  1. Characterized by intestinal type neoplastic glands similar to colonic adenomas
  2. Commonly associated with diffuse high grade dysplasia in the background gallbladder; connotes high risk for entire biliary tract
  3. Squamoid morules that show beta catenin nuclear labeling are common
  4. Typically associated with invasive carcinoma
  5. Usually seen in gallbladders with severe chronic inflammation
Board review style answer #1
C. Squamoid morules that show beta catenin nuclear labeling are common

Comment Here

Reference: Intracholecystic tubular nonmucinous neoplasm (ICTN)
Board review style question #2
Which of the following is characteristic for intracholecystic tubular nonmucinous neoplasm (ICTN) of the gallbladder?

  1. Intestinal differentiation
  2. Prominent papillary architecture
  3. Salt and pepper chromatin
  4. Squamoid or meningothelial-like morules
  5. Tubule forming cells with abundant mucin
Board review style answer #2
D. Squamoid or meningothelial-like morules

Comment Here

Reference: Intracholecystic tubular nonmucinous neoplasm (ICTN)
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