Figure 2.

Histological distinction features of iCCA. (A) Adenocarcinoma forming solid sheets; (B) with cuboidal cells; (C) Infiltrative glands composed of prismatic cells. Different histological growth patterns of iCCA showing (D) a mass-forming (MF) tumor, (E) a tumor showing intraductal growth (IG), and (F) a tumor with periductal-infiltrating growth. Note the adjacent inconspicuous biliary epithelium (inlay; (E,F)). (G) Biliary intraepithelial neoplasia of low-grade and (H), 200X magnification) high-grade; (I) intraductal papillary neoplasm of the bile ducts. Different amounts of mucin: (J) little mucin with PAS-positivity showing in the inlaid picture; (K) moderate and (L) extensive amounts of mucin. (M) Lymphangioinvasion and (N) lymph node metastasis. (O) Perineural invasion.