Figure 2.

Case  2. (a) Contrast-enhanced CT shows a cystic lesion (60 mm in diameter) with an enhanced wall near the hepatic hilus. (b) A cystic tumor with fibrous wall is found in segment 4, adjacent to the hepatic hilus. (c) Histologically, well-differentiated papillary adenocarcinoma with thin fibrovascular cores fills the cystic space of the tumor. ^∗ Surrounding nonneoplastic bile duct. Original magnification, 30x; H&E staining. (d) Papillary carcinoma with columnar epithelia and fine fibrovascular cores. Original magnification, 120x; H&E staining. (e) Invasion of carcinoma (∗) in the periductal tissue of adjacent bile ducts. The arrow denotes the nonneoplastic peribiliary glands. Original magnification, 100x; H&E staining. (f) Papillary carcinoma is positive for MUC6. Original magnification, 100x; immunostaining for MUC6.