case_images: PMC5968303_01
case_images: CT image with adjusted plane showing a double duct sign (a) and a dilated common bile duct (b).
case_images: crg-0012-0194-g01.jpg
case_images: PMC5968303_01_crg-0012-0194-g01.jpg
case_images: F1
case_images: Computed tomography showed a double duct sign (Fig. 1).
case_images: a Low-power view of the ampullary tumor, infiltrating in the mucosa, submucosa, and inner muscularis propria of the duodenum. HE. x20. b High-power magnification, showing preexisting duodenal crypts (right) and submucosa (right) infiltrated by signet ring cells. HE. x200.
case_images: crg-0012-0194-g02.jpg
case_images: PMC5968303_01_crg-0012-0194-g02.jpg
case_images: F2
case_images: A histological biopsy showed an adenocarcinoma with the characteristics of signet ring cells (Fig. 2). Histopathological findings showed an SRCC of 1.2 cm, poorly differentiated, without peripancreatic invasion, lymph node involvement, angioinvasion, or perineural invasion (Fig. 2, 3).
case_images: Immunohistochemical staining of the ampullary tumor, with benign tissue on the left border of each image. Positive staining for CK-19 (a), CK-20 (b), MUC-1 (c), MUC-2 (d), CDX-2 (e), DPC-4 (f), and negative for MUC-5ac (g).
case_images: crg-0012-0194-g03.jpg
case_images: PMC5968303_01_crg-0012-0194-g03.jpg
case_images: F3
case_images: Immunohistochemical staining showed that the signet ring cells were positive for CK20, CK19, MUC-1 (weak), MUC-2, CDX-2, and DPC-4, and negative for CK7, ER, GCDFP, and MUC-5ac (Fig. 3). Histopathological findings showed an SRCC of 1.2 cm, poorly differentiated, without peripancreatic invasion, lymph node involvement, angioinvasion, or perineural invasion (Fig. 2, 3).