Extrahepatic bile ducts
Tumors
Biliary intraepithelial neoplasia


Topic Completed: 1 September 2012

Revised: 13 September 2019

Copyright: 2003-2019, PathologyOutlines.com, Inc.

PubMed Search: Extrahepatic bile ducts biliary intraepithelial neoplasia

Hanni Gulwani, M.B.B.S.
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Cite this page: Gulwani H. Biliary intraepithelial neoplasia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/gallbladderBilIN.html. Accessed September 16th, 2019.
Definition / general

BilIN1:
  • Flat or micropapillary, basal nuclei, pseudostratification (within lower two thirds of epithelium)
  • Mild nuclear abnormalities

BilIN2:
  • Flat, pseudopapillary or micropapillary architecture
  • Loss of cellular polarity
  • Pseudostratification (reaching the luminal surface), dysplastic nuclear changes
  • Peribiliary glands are sometimes involved
  • Mitoses are rare

BilIN3:
  • Pseudopapillary or micropapillary architecture
  • Cytologically resembles carcinoma but no invasion
  • 'Budding off' of small clusters of epithelial cells
  • Severe nuclear membrane irregularities
Differential diagnosis
  • Hyperplasia or regenerative change: flat or low papillae, nuclear membrane smooth with fine chromatin, intraepithelial neutrophil infiltration can be seen; variable mitotic figures
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