Abstract

The distinction of carcinomas involving periampullary region is often difficult, even in the surgically resected specimens. To examine the differences in the expressions of cytokeratin (CK) 7 and 20 in the periampullary carcinomas, we performed immunohistochemical studies on surgically resected 20 pancreatic duct adenocarcinomas (PDA), 13 distal bile duct adenocarcinomas (DBA), 10 duodenal adenocarcinomas (DA), and 18 ampulla of Vater adenocarcinomas (AVA). We analyzed the relationships between CK 7/CK 20 immunoprofile, and tumor cell differentiation and tumor size. We interpreted diffuse cytoplasmic reactivity found in > or =5% of tumor cells as positive. In the majority of cases, PDA were CK 7 /20 (95%), DBA CK 7 /20 (92.3%), DA either CK 7 /20 (40%) or CK 7 /20 (30%), AVA either CK 7 /20 (50%) or CK 7 /20 (44.4%). In DA, there was an increased CK 20 negativity in less differentiated (moderately or poorly differentiated) cases (p<0.05) and in larger (> or =5 cm) tumor size (p=0.049). In AVA, there was a tendency of increased CK 20 positivity in less differentiated cases (p=0.10). In conclusion, the CK 7/CK 20 immunophenotype is useful in the differentiation of periampullary carcinomas: the CK 7 /CK 20 immunophenotype strongly suggests DA or AVA, whereas the CK 7 /CK 20 immunophenotype suggests PDA or DBA.

• Keywords: Periampullary carcinoma;Cytokeratin 7;Cytokeratin 20;