case_images: PMC4722727_01
case_images: Computed tomographic scan shows the presence of common bile duct-obstructing homogeneous mass (arrows). a Coronal view. b Axial view
case_images: 13256_2015_789_Fig1_HTML.jpg
case_images: PMC4722727_01_13256_2015_789_Fig1_HTML.jpg
case_images: Fig1
case_images: On the basis of the tumor's radiological features, a preoperative diagnosis of extrahepatic bile duct malignant tumor was made (T1N0M0, type I, by Bismuth-Corlette classification) (Fig. 1).
case_images: Surgical-pathological findings of a tumor inside the bile duct. a Intact bile duct. b Dissected bile duct
case_images: 13256_2015_789_Fig2_HTML.jpg
case_images: PMC4722727_01_13256_2015_789_Fig2_HTML.jpg
case_images: Fig2
case_images: The resection margin was 2 cm from one side and 2.5 cm from the other, and two investigated lymph nodes were identified as tumor-free (Fig. 2).
case_images: Microscopic examination (hematoxylin and eosin-stained slides). a General view of the tumor shows villous pattern of growth (original magnification, x6). b Cytological details of the tumor cells: slight nuclear atypia with no invasive growth (original magnification, x68). c Strong nuclear reaction with MSH2 immunomarker (original magnification, x98)
case_images: 13256_2015_789_Fig3_HTML.jpg
case_images: PMC4722727_01_13256_2015_789_Fig3_HTML.jpg
case_images: Fig3
case_images: Histologically, the tumor consisted of branching papillary structures lined by tall columnar epithelium with slight nuclear atypia and scant fibrous stroma (Fig. 3a, b). PMS2, MSH2, and MSH6 proteins. Positive nuclear immunostaining was observed in tumor cells (Fig. 3c), which showed no evidence of microsatellite instability.