Precursors to Cholangiocarcinoma

Table 1

Classification and characterization of biliary intraepithelial neoplasia (based on Ainechi S, Arch Pathol Lab Med 2016).

	BilIN-1	BilIN-2	BilIN-3
Cells	Polarity maintained; Increase in basally placed nuclei	Loss of polarity; Nuclei reaching the luminal surface	Marked loss of polarity; Nuclei reaching the luminal surface
Nuclei	Mild atypia	Moderate atypia	Severe atypia
Architecture	Flat	Flat or micropapillary	Likely micropapillary
Mitosis	Rare	Rare	Likely
Dysplasia	Low-grade	Intermediate	High-grade/carcinoma in situ