Figure 3

Microscopic findings of the pyloric gland adenoma and adjacent bile duct lesions. On microscopic view, the pyloric gland adenoma arose in the cystic duct (right) and displayed a papillary, intraluminal growth pattern with protrusion into the common bile duct (left) (A, H&E, x40). Closely packed pyloric type glands were lined by cuboidal to columnar mucus-secreting cells (B, x100) with focal architectural distortion (C, x100) and high-grade dysplasia with nuclear atypia, indicating transition into well-differentiated adenocarcinoma (D, x200). Focal high-grade intraepithelial neoplasia (BilIN-3) of the cystic duct was detected (E, x200), focally resembling gastric-type intraductal papillary neoplasm (IPN) with direct transition into the pyloric gland adenoma (F, x200).