Periampullary carcinoma: some important news in histopathology.

Incidence of periampullary carcinoma is low, approximately 0.5-2% of all gastrointestinal malignancies and 20% of all tumours of the extrahepatic biliary tree [1, 2, 3]. Peri-ampullary carcinoma arises around the confluence of the common bile duct with the main pancreatic duct and therefore may have a different anatomical origin: at the level of the pancreatic head (60% of the resected specimens), ampulla of Vater (20%), distal common bile duct (10%) and duodenum (10%) [4]. In clinical practice, all these kind of periampullary carcinoma are joined by the occurrence that they have a higher frequency of resectability compared to the pancreatic head cancers, which represent as much as 90% of the tumours (both resectable and unresectable) of the periampullary area. The clinical picture of periampullary carcinoma is mainly related in the vast majority of patients to an early occurrence of jaundice, thus contributing to the early detection and a higher resection rate. The macroscopic appearance of periampullary carcinoma includes: a) intramural tumours – inside the ampulla, without any protrusion inside the duodenum; b) extramural tumours – polypoid tumours protruding through the ampullary orifice into the duodenum, c) ulcerative cancers of the ampulla, which is associated with the worst prognosis [5]. According to the microscopic classification, there are two main histological types of periampullary carcinoma: the “intestinal type” (similar to tubular carcinoma of the stomach or the colon and the “pancreatobiliary type” (characterized by papillary projections with scant fibrous cores) [6] Immunohistochemical staining pattern of apomucins and cyto-keratins is different for the two periampullary carcinoma histological types: positivity for MUC2, CK20, CDX2 and CD10 is typical of the periampullary carcinoma-intestinal type whereas positivity for MUC1 and CK7 is predominant in pancreaticobiliary adenocarcinomas. Due to the rarity of this malignancy, the paucity of specific papers and the absence of prospective trials no relevant data have been available for the scientific community till the last few years. Quite recently, some articles focused on diagnostic assessment [7, 8, 9] and treatment modalities [10, 11, 12, 13, 14] have been published thus filling a lot of gaps. On this concern, some very interesting features come from recent advances in periampullary carcinoma pathology.