“…From a histological point of view, intestinal-type AC is usually characterized by the presence of a non-invasive component of duodenal adenoma, and the morphology of this subtype has been suggested to be similar to that of colorectal cancer, with central necrosis and cribriform or tubular glands [ 13 , 14 ]. Classically, intestinal-type ACs present a smaller invasive component and less frequent perineural and lymphovascular invasion, something that has been related to a better prognosis compared to pancreaticobiliary-type ACs [ 15 , 16 ]. In terms of immunohistochemistry, intestinal-type AC frequently presents the expression of cytokeratin 20 (CK20), mucin 2 (MUC2), caudal-related homeodomain transcription factor 2 (CDX2) and other classically intestinal markers [ 15 , 16 ]; conversely, the pancreaticobiliary subtype has important immunohistochemical analogies with distal cholangiocarcinoma and pancreatic adenocarcinoma, due to the presence of abundant desmoplastic stroma and atypical cells [ 15 , 16 , 17 ], and the frequent immunohistochemical expression of mucin 1 (MUC1), cytokeratin 7 (CK7), and mucin 5AC (MUC5AC) [ 15 , 16 , 17 ].…”