Intraoperative frozen section diagnosis of bile duct margin for extrahepatic cholangiocarcinoma

Figure 2 Discordance between frozen section diagnosis and permanent section diagnosis. Bile duct margin of Case 172 (dCCA) prepared for FSD (A) and PSD (B), and that of Case 157 (dCCA) prepared for FSD (C) and PSD (D) (hematoxylin and eosin, 20 ×). These two sets of figures represent the same region of the bile duct margin, respectively. Epithelium was detached from subepithelium, denatured, twisted, and FSD was borderline (BilIN-2) (A), while PSD was negative (B). Epithelium was severely denatured owing to artifacts and FSD was negative (C), while BilIN-3/carcinoma in situ appeared in different sections prepared for PSD (D). FSD: Frozen section diagnosis; PSD: Permanent section diagnosis; dCCA: Distal cholangiocarcinoma; BilIN: Biliary intraepithelial neoplasia.