Extrahepatic bile ducts
Tumors
Biliary intraepithelial neoplasia

Author: Hanni Gulwani, M.D. (see Authors page)

Revised: 8 February 2018, last major update September 2012

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Extrahepatic bile ducts biliary intraepithelial neoplasia

Cite this page: Gulwani, H. Biliary intraepithelial neoplasia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/gallbladderBilIN.html. Accessed June 18th, 2018.
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