Intraoperative frozen section diagnosis of bile duct margin for extrahepatic cholangiocarcinoma

Figure 1 Representative histopathology of BilIN-1, 2, and 3 by frozen section diagnosis. A: Normal mucosa; B: Borderline (BilIN-1); (C) Borderline (BilIN-2); and D: Positive (BilIN-3) (hematoxylin and eosin, 20 ×). BilIN: Biliary intraepithelial neoplasia.

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.

Figure 3 Local recurrence-free survival analysis according to the frozen section diagnosis status. The Kaplan-Meier curves of patients with eCCA according to the status of the bile duct margin evaluated by FSD in total layer (A) and epithelial layer (B). Patients with borderline or positive subepithelial layer were excluded from the analysis in the epithelial layer. Black line: negative; Red line: borderline; Green line: positive; eCCA: Extrahepatic cholangiocarcinoma; FSD: Frozen section diagnosis.

Figure 4 Local recurrence-free survival analysis according to the permanent section diagnosis status. The Kaplan-Meier curves of patients with eCCA according to the status of the bile duct margin evaluated by PSD in total layer (A) and epithelial layer (B). Patients with borderline or positive subepithelial layer were excluded from the analysis in the epithelial layer. Black line: negative; Red line: borderline; Green line: positive; eCCA: Extrahepatic cholangiocarcinoma; PSD: Permanent section diagnosis.